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Comprehensive Memory Overclocking Guide

Welcome to my memory overclocking guide. Before we get started, there are a few things I want to get out of the way, along with a few people to thank. First of all, thank you to @SteveGrabowski0 for being my partner in crime in this sub-forum, spreading the word about memory and it's impact on gaming performance. I would also like to thank @done12many2 for reigniting my passion for memory overclocking. Seeing you take to it so quickly, gave me hope that I could improve upon what I already had, and I did. Lastly, I would like to thank a friend who is not a part of this forum, but he's the man that got me into computers in the first place. He was also the one to teach me every timing in explicit details. Thanks Matt, a man could never ask for a better OCD stricken, unrealistically high standards friend. 

 

Now, for the disclaimer: Memory overclocking will drive you insane. There is no one-stop overclock that will work for all boards, CPU's, etc. When I say it's trial and error, I mean it. You will either hate it, and never do it again, or become so addicted to it that it consumes your free time. Normally with a disclaimer; someone would say "this is your own doing, I am not liable for damage, bla bla bla" but let's face it, the only way you will damage your system with memory overclocking, is if you completely abandon all common sense. Stay within the voltages I put in this guide, and you will be perfectly fine. Now... let's get this show on the road.

 

Part 1: Intel

For this first part, we will be focusing on Intel boards and CPU's, since this is where I have the most expertise. Most of the timings we will be touching, are available on both DDR3 and DDR4, so a lot of this knowledge is interchangeable. Let's start with terminology:

 

Voltages: Below, are a list of voltages we will use when overclocking our memory to improve stability. I'll include both DDR3 and DDR4 voltages, along with Intel's "recommended max" voltages for the users that wish to have peace of mind. These voltages are:

  • vDIMM (Sometimes called VDDQ or DRAM Voltage, supplied from the board to the memory itself)
  • VCCIO (Voltage for the path going into and out of the IMC)
  • VCCSA (Sometimes called System Agent Voltage, it's your IMC and PCIe subdomain voltage)

For DDR3, typical voltages are 1.35v (DDR3L), 1.5v (JEDEC DDR3), and 1.65v (OC'd DDR3). Intel's max recommended voltage for DDR3 on Sandy/Ivy/Haswell, is 1.5v +5%, which is 1.575v. For DDR4, typical voltages are 1.2v (JEDEC DDR4), and 1.35v (OC'd DDR4). Intel's max recommended voltage for Skylake's DDR4 half of it's IMC is 1.2v + 5%, which is 1.26v. For the DDR3 half of Skylake's IMC, it's 1.35v + 5% which is 1.4175v. Sources to these claims (and why I think they are bogus) can be found here: 

For VCCIO/VCCSA, I do not recommend exceeding a value of 1.25v for each. I personally use a value of 1.14v for VCCIO, and 1.15v for VCCSA. Going beyond 1.25v is silly, and may potentially damage your IMC or traces on your board.

 

Primary Timings: These are timings that are normally listed on every sales page of your ram. They include:

  • CAS Latency (tCL)
  • RAS to CAS delay (tRCD)
  • Row Precharge Time (tRP)
  • RAS Active Time (tRAS)
  • Command Rate (CR) (Note: Command Rate is not a timing, but it's listed under Primary Timings, so I included it here)

They are also commonly available to tinker on most chipsets, and are often made available for tuning in software like XTU.

 

Secondary Timings: These are timings that are seldom ever listed anywhere on a marketing page, but you can find them within your BIOS on some chipsets. They include:

  • Write Recovery Time (tWR)
  • Refresh Cycle Time (tRFC)
  • RAS to RAS Delay Long (tRDD_L)
  • RAS to RAS Delay Short (tRDD_S)
  • Write to Read Delay Long (tWTR_L)
  • Write to Read Delay Short (tWTR_S)
  • Read to Precharge (tRTP)
  • Four Active Window (tFAW)
  • CAS Write Latency (tCWL)

Most of these timings are inaccessible on lower-end chipsets and more restrictive BIOS's. Very rarely will you have access to them on lower-end configurations, and even XTU lacks control over most of these timings.

 

Tertiary Timings: These are timings that are NEVER listed anywhere on a marketing page, and are different per motherboard/CPU IMC/ ram IC. They are generated by your IMC, after your board probes it repeatedly looking for a stable configuration. Some of you might have noticed your PC restarting a few times when installing new memory kits. These timings are often the cause of that, as they need special training in order for you to post properly. They include:

  • tREFI
  • tCKE
  • tRDRD (_SG, _DG, _DD, _DR)
  • tRDWR (_SG, _DG, _DD, _DR)
  • tWRRD (_SG, _DG, _DD, _DR)
  • tWRWR (_SG, _DG, _DD, _DR)

SG = Same Group, DG = Different Group, DD = Different DIMM, DR = Different Rank. Credit to @Digitrax for providing this information.

Very specific boards and chipsets will allow modification of these timings. They are by far one of the most important groups of timings you can adjust, and are directly involved in improving your bandwidth efficiency. More on that later.

 

Round Trip Latency: Since these settings are not timings, and are not always listed under tertiary timings, I feel they need their own section, as they are probably the single most important settings you can adjust to see the biggest impact on performance. They include two settings:

  • RTL (the title of this section should give you hints as to what this is)
  • IO-L

As the title of this section hints at, Round Trip Latency is directly involved in how long it takes your ram to complete it's total cycles. The tighter this value is, the lower your overall latency is. Sounds great, right? Well, the problem is: literally every timing is associated with this setting, and tightening other settings, makes it harder to tighten this. It's also annoying to adjust, as you cannot adjust it without also adjusting IO-L settings (the two must be adjusted as a pair) and there is no secret formula for doing so. All I can tell you is: your RTL channels cannot be more than 1 apart in either direction. Example: If RTL of Channel A is 50, RTL of Channel B can be 51 or 49. It cannot be 52 or 48, as this will result in extremely terrible performance, or worse, system instability.

 

Now that we have the timing terminology out of the way, let's first discuss stability testing. After all, you cannot overclock until you know how to validate that overclock.

 

Stress Testing (Validating Stability)

This part is always met with some sort of controversy, as everyone has their own way of doing things. That being said, I too have my own way, and it's the only way I've ever done it, so I'll have to stick by what I know. When making adjustments in your BIOS for timings or frequency, I always recommend running a full pass of memtest86. Memtest86 is not a stress test, but it will test things that can potentially show your IMC not liking your current memory configuration. I use it as a precursor to actual memory stress testing, as it helps prevent instant crashing in Windows due to IMC outright hating your memory configuration. We use memtest86 in two phases: 

 

Phase 1: Full Pass

Phase 2: IMC Smackdown.

 

Phase 1 is pretty self explanatory. It's running memtest86, using all 13 tests. Phase 2 is where the fun begins, as we disable all tests excluding test 6, and run it several times. I personally do 10 runs of test 6, but feel free to do however many you wish to do. It will test different rows and addresses with each subsequent test, so the more you run it, the better your chances are for finding IMC/RAM incompatibility. This phase is critical when making adjustments to tertiary timings, as this test will find issues quicker than any other. When using Memtest86, make sure you hit C, and select "All Cores: Parallel". This will make the test go much quicker. Believe me, you will want to save as much time as you can, as memory overclocking takes a long time to validate 100% stability.

 

Next, we have my tool of choice for basically all forms of stress testing, Prime95. I know, some of you are scared when you see this come up. In fact, pretty sure I felt someone's heartbeat increase somewhere in the world due to the sheer mention of it. Relax. For this purpose, Prime95 is going to be 100% harmless. In fact, we won't be using an FFT size small enough for it to get hot, so you should be fine. If you are absolutely terrified, feel free to use the non-AVX version, as it shouldn't matter for ram stability (unless you are stress testing specific AVX-based tertiary timings, such as tRDWR_DD/DR, but more on that later. For now, let's focus on how to stress it. Open up Prime95 of your choice (I am currently using 28.10 as of this guide) and input the following settings:

VsAPTEW.png

(Do note: Number of threads should be equivalent to the amount of threads available on your processor. For example, a 7700k has 8 threads, while an R7 1700 has 16)

Now, for "Memory To Use", make sure you enter your own value. I highly recommend 75% of your total capacity. If you have say, 16GB, then your capacity = 16 x 1024 - 25% = 12288MB. For 8GB, that value would be 6144MB. Since I have 32GB, I'll be using 24576 to stress test. Once this starts, let it run for several hours. I personally let mine run for about 8-12 hours, depending on how I feel and how much I've tinkered from my last stable profile, but I do not recommend running for less than 8 hours. I know it's tempting to cut corners, but memory instability is not a game you want to play. It can seriously corrupt your windows installation, and require a fresh install. Take this part seriously.

 

As for why we use the settings above, allow me to explain. 512k-1024k is hard on the IMC and IO lanes. 2048k+ is hard on your ram. By setting the range at 512-4096, we not only stress the IMC and IO Lanes, we also stress the memory itself. Be warned: 1344k and 2688k are also included in this range, and are the hardest stress on vCore. If your CPU is unstable by any means, it will fail this, and will likely hold you back on memory overclocking. Always make sure your CPU is 100% stable before attempting memory overclocking. The less variables involved, the better. For those of you with Haswell, and worried about that old myth of Prime95 killing CPU's, understand this. This range lacks 448k, which was the hardest FFT to test on FIVR. You should be fine here.

 

 

Overclocking Memory (Intel Platforms)

Precautions: The very first thing I advise you do, is locate your CLEAR_CMOS button on your motherboard (if you have one) or put your system in a location that adjusting your CMOS jumpers/battery is easily accessible. You are certainly going to be using them, no exceptions. Next be sure to have your power supply's power cable near you. Sometimes, removing this and holding down the power button for 60 seconds, results in enough of a clear to allow you to get back into BIOS without completely resetting everything. Lastly, save all of your "pseudostable" profiles, so that you can continue to adjust them for better stability without starting over.

 

Overclocking Time!: Now that we have the precautions out of the way, it's time to start tinkering. I recommend focusing on Frequency first, while keeping your primary timings the same. I personally dial in a vDIMM of 1.35v, and then I start increasing my memory frequency one memory strap at a time. If I was at 3000 C15, I would try 3200 C15, then 3333 C15, 3466 C15, and so on. When you reach a point to where it no longer posts, you have 3 options. Option 1: Throw more voltage at it. Option 2: Loosen your primary timings. Option 3: settle for last bootable configuration. 

 

I advise trying option 1 first, as it might only take a little bit more vDIMM to make it stable. For example: My 3600 C14 profile is unstable at 1.35v, but stable at 1.39v. Since it's still under the "1.4175v" that Intel suggested for the DDR3 half of the IMC, I just pretend the DDR4 half of my IMC will tolerate it just as well. As I've ranted about before, you won't be killing an IMC with vDIMM. Now, your VRM components near your ram on the motherboard, that's a different story entirely. Use common sense, and try to avoid going over 1.45v for 24/7 vDIMM and you should be fine. Some 4266 kits even use a value of 1.4v on their XMP's, and nobody has killed a board or CPU with those yet.

 

Option 2 is what we call "compromising". You have to be careful when making compromises on timings for speed. The end must justify the means. If you gain a slight amount of bandwidth, but lose on latency at all, it's a bad trade. Memory is already so ridiculously fast in regards to bandwidth, that latency should ALWAYS come first in your mind. That being said, frequency can be just as good for latency as it is with bandwidth. It just takes a little balance. If you increase frequency while keeping timings the same, latency improves. If you loosen latency while increasing bandwidth, one of two things can happen. #1: you have faster bandwidth, and latency remains the same as a result. This is a good trade with no negative side effects, so I tend to allow this. #2: you gain bandwidth, but latency suffers. This is a terrible trade, and should never be made. Go back to your last configuration, and work on making that stable instead.

 

When making minor tweaks, I recommend using software like Aida64's memory bandwidth test (cachemem test) to see your gains in performance. Yes, I know it sucks using paid software, but it seriously helps with knowing whether or not your timings are making a positive or negative impact in performance. While I do intend to provide the list of timings that benefit performance regardless of your memory IC's, you must understand that certain IC's have specific tertiary timings that they benefit from being loose, or tight. I cannot tell you a Samsung timing configuration, that will also boost your Hynix timing configuration, because they both enjoy completely different values. You can also have two different Samsung IC's (B Die, D Die, etc) that also prefer different values. The best course of action in this scenario, is trial and error.

 

Now that we've gotten frequency and primary timings taken care of, it's time for secondary timings. While you will see small gains from most of these timings, I want to focus on one very important secondary timing. tRFC. You see, memory is a matrix of billions of capacitors that need to be recharged. You have tRFC, a secondary timing, that works alongside tREFI, a tertiary timing. Every <tREFI>, they are recharged in order, for <tRFC> amount of time. Simply put: tRFC is the mount of time your ram can do nothing, while being recharged. tREFI = the amount of time your ram can do things, before needing recharged. Both are very important, and have significant impact on your latency. tRFC works best as low as you can get it, and tREFI functions best as high as you can get it. tRFC, in my testing, is best left at 270, as it's the easiest value to keep stable, while having the best gains in performance. tREFI on the other hand, can go as high as 65535 and not really matter, but can potentially lead to corruption if your motherboard's quality is lackluster. The warmer your DIMMS, the more often they need recharged. If mobo is bad, it can't recharge high enough to meet the required interval. Basically, if motherboard is bad, stick to the JEDEC standard of 7.8usec refresh interval. If your ram is 3000mhz, the formula is 1500 x 7.8 = 11700. If your ram is 3600mhz, the formula would be 1800 x 7.8 = 14040 tREFI.

 

There are other formula's for your secondary timings worth following, such as: tFAW = tRRD x 4. The others, they tend to take trial and error. Gain's can be small, or big, depending on whether or not you are using DDR3 or DDR4. I can say that with DDR4, the gains are not as massive as touching tertiary timings. Speaking of which...

 

Tertiary timings: Depending on your level of masochism, this will be the part you love the most, or absolutely dread. There is no in-between. As you saw above during the terminology half, tertiary timings tend to have a few suffixes after their name. These are SG, DG, DD, and DR. I'll be frank here. I have no idea what SG or DG means, I just know that they severely impact your bandwidth, no matter what kind of memory you use. As for DD, I believe these are related to 2DPC (DIMMS Per Channel) and only matter if you have 2 DIMMS per channel (ITX users rejoice, less complication) while DR matters when using multi-rank kits. It's easier to associate DR with "Dual Rank". If you have a single rank kit, touching _DR timings does literally nothing. No positive or negative, and no instability issues either. I recommend taking these one at a time, or at the very least, one group at a time. Focus on tRDRD (and all of it's suffixes), followed by tRDWR, and so on. Fun fact about tRDWR: these timings directly impact AVX. The tighter they are, the hotter AVX is. The looser they are, the cooler AVX is. Those of you that fear AVX, you might be able to use this to your advantage, and make those stress tests easier on yourself. I promise not to judge you.

 

EDIT: Huge thanks to Digitrax for providing clarification on what these tertiary timings mean. Look at his post below for details:

12 hours ago, Digitrax said:

From you article: "I'll be frank here. I have no idea what SG or DG means..."

"SG" is "Same Group" (meaning the same memory page)

"DG" is "Different Group" (the same way that "DR" is "Different Rank" and "DD" is "Different DIMM")

 

Thoroughly enjoyed your guide, though.

 

Once you've finally settled on your tertiary timings, and have gone through countless hours of stress tests, it's time for the bane of my existence. RTL/IO-L's. I honestly cannot give you any better advice, other than "You gotta feel it". There is no magical value that I can tell you to dial in, and have it work. You can ask me until you are blue in the face, and I simply will not be able to help you. RTL has one very specific value it likes, and a few others that it "tolerates", and that's it. Either it works, trains poorly, or doesn't work at all. Now, with DDR4, we do have a trick up our sleeves to at least prevent it from training poorly. It's a very simple formula for a specific setting, called RTL Init. This formula is: IO-L + IO-L Offset + CL (x2) + 10. Let's say your IO-L is 4, and your offset is 21. You have a CAS Latency of 14. The formula would be: 4 + 21 + 14 (x2) + 10 = 63. Once you input 63 in the RTL Init setting, your IMC will no longer train RTL's beyond it's current threshold. This is great, as it at least prevents performance from getting worse. However, this is only a band-aid. You should still strive to find optimal settings for RTL/IO-L. That being said, do not beat yourself up dwelling on this. If you've gained significant strides in all other aspects of your ram, then feel proud of what you've accomplished. It's still worlds beyond what XMP can offer you, and you've gotten one step closer to mastering one of the most difficult "overclocking disciplines" there is. 

 

For those of you that expected more than this, I am sorry. I am still learning myself, and I do not feel that I understand every aspect yet, so bare with me as I continue to learn and update this "guide" with what I discover in the future. If I forgot to tag anyone that was waiting to read this, I apologize, as my mind has been elsewhere and I honestly cannot remember who was waiting to read this. Part 2 (AMD Classic) and Part 3 (AMD Ryzen) will be coming as soon as I get the time. It may take weeks or even months for those to be completed, as my free-time is very scarce at the moment. As for why I need two entirely different parts for AMD, It's simple. Ryzens IMC is a complete overhaul over AMD's older architectures. It resembles absolutely nothing if it's former IMC (for better or for worse) and is currently lacking in many features. Simply put: Overclocking Ryzen's memory isn't an easy task, even for veterans. It requires a lot of tricks and luck, far more than any other platform I've encountered. 

 

When I get additional time, I'll amend some of this guide to try to make it easier to understand, as well as add my experiences and additional tricks to save time during this process. Good luck everyone, hope it helps. 

Edited by MageTank
Updating information based on user feedback

My (incomplete) memory overclocking guide: 

 

Does memory speed impact gaming performance? Click here to find out!

On 1/2/2017 at 9:32 PM, MageTank said:

Sometimes, we all need a little inspiration.

 

 

 

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Reserved for Part 3: AMD Ryzen

 

EDIT: https://community.amd.com/community/gaming/blog/2017/05/25/community-update-4-lets-talk-dram

 

AMD has released a new AGESA update, along with clearer definitions of timings and how they work with their IMC. Their information seems very spot on, and should serve as a great foundation for new memory overclockers. I still do not see RTL/IO-L settings, but this is a huge start for fine-tuning performance and stability. 

My (incomplete) memory overclocking guide: 

 

Does memory speed impact gaming performance? Click here to find out!

On 1/2/2017 at 9:32 PM, MageTank said:

Sometimes, we all need a little inspiration.

 

 

 

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@MageTank

 

Thanks for taking the time to create this and for formatting it in a manner that most should be able to digest.  This took a lot of time and effort.  I appreciate it!

 

Admin/mods, I believe this would better benefit the community if it was a sticky within the CPUs, Motherboards, and Memory section. Not only will it be easier to access, but it will force @MageTank to maintain it over time.  Increasing the burden on him seems like the right thing to do.  xD

 

@Whaler_99

@0ld_Chicken

@Energycore

@Godlygamer23

@leadeater

@Ryan_Vickers

 

 

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Just now, done12many2 said:

@MageTank

 

Thanks for taking the time to create this and for formatting it in a manner that most should be able to digest.  This took a lot of time and effort.  I appreciate it!

 

Admin/mods, I believe this would better benefit the community if it was a sticky within the CPUs, Motherboards, and Memory section. Not only will it be easier to access, but it will force @MageTank to maintain it over time.  Increasing the burden on him seems like the right thing to do.  xD

 

@Whaler_99

@0ld_Chicken

@Energycore

@Godlygamer23

@leadeater

@Ryan_Vickers

 

 

I was afraid someone would do this. With my work schedule, I am afraid that it will be difficult to answer every question that is asked of me, and I am sure there will be many (as the subject can be quite daunting for first timers). I just figured I would add it to my sig, and let those curious enough to read my sig, ask the questions. 

My (incomplete) memory overclocking guide: 

 

Does memory speed impact gaming performance? Click here to find out!

On 1/2/2017 at 9:32 PM, MageTank said:

Sometimes, we all need a little inspiration.

 

 

 

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3 minutes ago, MageTank said:

I was afraid someone would do this. With my work schedule, I am afraid that it will be difficult to answer every question that is asked of me, and I am sure there will be many (as the subject can be quite daunting for first timers). I just figured I would add it to my sig, and let those curious enough to read my sig, ask the questions. 

 

The fact of the matter is, I see more threads about memory overclocking then I do about topics currently at the top of this section.  There are plenty of folks around to help out as questions pop up.

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4 hours ago, done12many2 said:

 

The fact of the matter is, I see more threads about memory overclocking then I do about topics currently at the top of this section.  There are plenty of folks around to help out as questions pop up.

How many of them will "help" correctly though? :P 

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If you can read this you're using the wrong theme.  You can change it at the bottom.

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Question: why do Intel's non z motherboards support XMP if they can't overclock ram?

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1 minute ago, MyName13 said:

Question: why do Intel's non z motherboards support XMP if they can't overclock ram?

Honestly, it depends on the board manufacturer. ASrock has their Hyper lineup which does support overclocked memory, on a non-overclocking platform. It's done using an external clock generator, and often requires manipulation of the System Agent Bus itself to pull off (hence the required dGPU usage). I am sure Intel frowns upon this, but I have not seen them put a stop to it just yet. http://www.asrock.com/mb/Intel/Fatal1ty H170 PerformanceHyper/?cat=Memory

34WwlR5.png

 

As for others, most of them just use XMP's to load specific information about the memory IC's themselves, to improve memory compatibility. All sticks are required to adhere to a JEDEC SPD profile, and all IC's must have a range of tertiary timings that comply with these speeds. Your XMP option can still load these JEDEC speeds, with improved compatibility. 

My (incomplete) memory overclocking guide: 

 

Does memory speed impact gaming performance? Click here to find out!

On 1/2/2017 at 9:32 PM, MageTank said:

Sometimes, we all need a little inspiration.

 

 

 

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  • 2 weeks later...

First off, thank you so much for creating this. it's super helpful. you're a hero.

 

Secondly, I have a few questions:

If my RAM has a small heat-spreader, should I be worried about overheating?

I've OC'ed my DDR3-1600 (9-9-9-24) to 2000Mhz (10-11-11-27), and would like to either raise my frequency a bit more, or tighten timings (both should drop latency)

However, I already have my voltage at 1.66V, so I won't go any higher.

 

I'm hoping secondary / tertiary timings can bump me higher to at least 2133Mhz, but with so many secondary and tertiary timings available, simply trying to tighten/loosen them randomly isn't practical, and I don't know which ones are important.

 

In a post on this thread: https://linustechtips.com/main/topic/777648-64gbs-of-ram-ocing/

you said this:

 

Spoiler

I say we focus on making 3200 work (that way, you at least get what you pay for) then throw all effort towards latency. If it were me, I'd focus on tertiary timings, specifically tRDWR_DR and tRDWR_DD. Loosening this won't impact bandwidth much, but will drastically lower AVX temperatures, and improve ram stability in general. Try to get tRFC as tight as you can, to get significant gains in the latency department, and pump up tREFI as high as you can get it. Since your board is no pushover, putting tREFI at 65535 should be perfectly fine for 24/7 use, and will also help latency by quite a bit.

 

Try to get tRFC down to around 270 if possible, and feel free to try for lower if you can do so while remaining stable. If you are still having issues with making 3200 work, make sure to tweak VCCIO and VCCSA a little, but don't go overboard. I do not recommend letting these exceed 1.25v each for 24/7. 

This is super informative, and it might be a good idea to add to your guide something about which timings are important in tertiary timings, and which ones to tweak if I want the best RAM speeds.

 

 

QUOTE/TAG ME WHEN REPLYING

Spend As Much Time Writing Your Question As You Want Me To Spend Responding To It.

If I'm wrong, please point it out. I'm always learning & I won't bite.

 

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6 hours ago, RadiatingLight said:

First off, thank you so much for creating this. it's super helpful. you're a hero.

 

Secondly, I have a few questions:

If my RAM has a small heat-spreader, should I be worried about overheating?

I've OC'ed my DDR3-1600 (9-9-9-24) to 2000Mhz (10-11-11-27), and would like to either raise my frequency a bit more, or tighten timings (both should drop latency)

However, I already have my voltage at 1.66V, so I won't go any higher.

 

I'm hoping secondary / tertiary timings can bump me higher to at least 2133Mhz, but with so many secondary and tertiary timings available, simply trying to tighten/loosen them randomly isn't practical, and I don't know which ones are important.

 

In a post on this thread: https://linustechtips.com/main/topic/777648-64gbs-of-ram-ocing/

you said this:

 

  Hide contents

I say we focus on making 3200 work (that way, you at least get what you pay for) then throw all effort towards latency. If it were me, I'd focus on tertiary timings, specifically tRDWR_DR and tRDWR_DD. Loosening this won't impact bandwidth much, but will drastically lower AVX temperatures, and improve ram stability in general. Try to get tRFC as tight as you can, to get significant gains in the latency department, and pump up tREFI as high as you can get it. Since your board is no pushover, putting tREFI at 65535 should be perfectly fine for 24/7 use, and will also help latency by quite a bit.

 

Try to get tRFC down to around 270 if possible, and feel free to try for lower if you can do so while remaining stable. If you are still having issues with making 3200 work, make sure to tweak VCCIO and VCCSA a little, but don't go overboard. I do not recommend letting these exceed 1.25v each for 24/7. 

This is super informative, and it might be a good idea to add to your guide something about which timings are important in tertiary timings, and which ones to tweak if I want the best RAM speeds.

 

 

Ram heatspreaders are seriously not needed. I've ran 1.7v on DDR3 without spreaders at all for years, with some very aggressive overclocks (2400 C9-11-11-20-1) and they never went beyond "warm to the touch". I personally don't care for larger heatspreaders, as they look gaudy and often interfere with larger CPU heatsinks.

 

BTW, with your primary timings, you can make them 10-11-11-21 and not have any issues. tRAS needs to be at least tRCD+tCL in order to be perfectly stable. Since your tCL is 10, and tRCD is 11, a tRAS of 21 will be perfectly fine, and the most efficient way to handle primaries. For secondary timings, set tWR to same as tCL and try to get tRFC as low as you can get it. Start at 300, and work your way down 10 at a time until it's no longer stable, then dial it back a little. This will yield huge improvements for your latency.

 

I'll try to update this guide as I get the free time to better include the information you seek, regarding which timings do what, and the order in which they need to be tweaked (from most important, to least important). Sadly, I have a rough work week and a trip I must take in the next two weeks, so finding the free time might be more difficult than one may think. 

My (incomplete) memory overclocking guide: 

 

Does memory speed impact gaming performance? Click here to find out!

On 1/2/2017 at 9:32 PM, MageTank said:

Sometimes, we all need a little inspiration.

 

 

 

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6 hours ago, MageTank said:

Ram heatspreaders are seriously not needed. I've ran 1.7v on DDR3 without spreaders at all for years, with some very aggressive overclocks (2400 C9-11-11-20-1) and they never went beyond "warm to the touch". I personally don't care for larger heatspreaders, as they look gaudy and often interfere with larger CPU heatsinks.

I knew water cooled RAM was seriously stupid but I didn't realize it was this unnecessary xD 

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I knew water cooled RAM was seriously stupid but I didn't realize it was this unnecessary xD 

I can actually put into perspective how dumb heatsinks are for ram these days. I currently have the heatsinks off my DDR4 kit, and even when heavily overclocked and used aggressively as a ramcache for my SSD (literally deferring all writes to my memory before touching my SSD) while running large FFT Prime95 (hits ram hard), my temps are only 55C+/- under arguably the most stressful kind of test for ram. Any type of active cooling near the ram will far exceed what you need to hit higher overclocks on ram. Simply having decent care airflow, or if ITX, having a fan over top of the ram area, is more than enough to keep ram cool. Technically speaking, ram is rated to run at up to 85C for general use:

G5jqdMp.png

9w7hoDh.png

 

BTW, if you look at the fourth note, it's basically saying if you go beyond 85C, you simply need to adjust tREFI to accommodate for the higher thermals. If tREFI is 10240, cut it directly in half to 5120 so that the time it waits before a recharge, is much sooner. This will have a negative impact on latency, but will help offset the high thermals. I have never had to do this personally, but it's yet another safeguard to take into account when worrying about ram thermals.

 

TL:DR? Ram heatsinks are a waste of time, and are only around to make ram look good aesthetically. There is a reason they still sell those plain ugly green PCB's that work just fine.

 

My (incomplete) memory overclocking guide: 

 

Does memory speed impact gaming performance? Click here to find out!

On 1/2/2017 at 9:32 PM, MageTank said:

Sometimes, we all need a little inspiration.

 

 

 

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*snip*

Given all that, I'd really like to know who's job it is to do #2 xD 

Solve your own audio issues  |  First Steps with RPi 3  |  Humidity & Condensation  |  Sleep & Hibernation  |  Overclocking RAM  |  Making Backups  |  Displays  |  4K / 8K / 16K / etc.  |  Do I need 80+ Platinum?

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Given all that, I'd really like to know who's job it is to do #2 xD 

Oh, it can still happen, but you'd have to go out of your way to make it happen. 65535 tREFI, super tight tRFC in an extremely poor airflow chassis on a board with awful VRM that overfeeds your voltages, yeah... disaster can strike in that scenario. Since those whitesheets are coming from Micron, it's safe to assume they design with the server environment in mind, with hot stagnant air being problematic for some clients. 

 

Either way, heat definitely should never be a concern for most users when ram is involved. That is to say, the ram itself. Specific ram timings can indeed have a dramatic impact on AVX performance/thermals. If you don't mind less float performance, you can totally make Prime95/Linpack run super cold, lol. 

My (incomplete) memory overclocking guide: 

 

Does memory speed impact gaming performance? Click here to find out!

On 1/2/2017 at 9:32 PM, MageTank said:

Sometimes, we all need a little inspiration.

 

 

 

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Oh, it can still happen, but you'd have to go out of your way to make it happen. 65535 tREFI, super tight tRFC in an extremely poor airflow chassis on a board with awful VRM that overfeeds your voltages, yeah... disaster can strike in that scenario. Since those whitesheets are coming from Micron, it's safe to assume they design with the server environment in mind, with hot stagnant air being problematic for some clients. 

 

Either way, heat definitely should never be a concern for most users when ram is involved. That is to say, the ram itself. Specific ram timings can indeed have a dramatic impact on AVX performance/thermals. If you don't mind less float performance, you can totally make Prime95/Linpack run super cold, lol. 

hm, good to know, and I guess that makes sense.  I just liked to imagine the guy who negotiates himself the job of designing the heat spreaders knowing full well you just sketch up whatever looks cool and call ti a day xD 

Solve your own audio issues  |  First Steps with RPi 3  |  Humidity & Condensation  |  Sleep & Hibernation  |  Overclocking RAM  |  Making Backups  |  Displays  |  4K / 8K / 16K / etc.  |  Do I need 80+ Platinum?

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  • 2 weeks later...
On ‎5‎/‎10‎/‎2017 at 2:29 AM, MageTank said:

BTW, with your primary timings, you can make them 10-11-11-21 and not have any issues. tRAS needs to be at least tRCD+tCL in order to be perfectly stable. Since your tCL is 10, and tRCD is 11, a tRAS of 21 will be perfectly fine, and the most efficient way to handle primaries. For secondary timings, set tWR to same as tCL and try to get tRFC as low as you can get it. Start at 300, and work your way down 10 at a time until it's no longer stable, then dial it back a little. This will yield huge improvements for your latency.

I haven't had time to try put these timings into effect until now, but when I tried 10-11-11-21, it didn't boot. it's only stable with a 27 tRAS... No idea why.

My RAM is 9-9-9-24 by default, so out of the box tRAS is already more than tRCD + tCL combined.

 

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5 minutes ago, RadiatingLight said:

I haven't had time to try put these timings into effect until now, but when I tried 10-11-11-21, it didn't boot. it's only stable with a 27 tRAS... No idea why.

My RAM is 9-9-9-24 by default, so out of the box tRAS is already more than tRCD + tCL combined.

 

Sounds like it's time to tweak tFAW. Let me know what your tFAW is set at. 

My (incomplete) memory overclocking guide: 

 

Does memory speed impact gaming performance? Click here to find out!

On 1/2/2017 at 9:32 PM, MageTank said:

Sometimes, we all need a little inspiration.

 

 

 

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On ‎5‎/‎19‎/‎2017 at 6:21 PM, MageTank said:

Sounds like it's time to tweak tFAW. Let me know what your tFAW is set at. 

@MageTank

these are all my timings currently.

tFAW is 24

 

By no means are you obligated to help me, and I'd completely understand if you only wanted to answer a few simple questions and leave it at that, but I'd really appreciate if you could guide me through the process of OC'ing my RAM, so I can understand what all the timings do, and how to OC RAM in the future.

 

Also: What helped you learn about OC'ing RAM. if there's a nice article explaining everything I'd love to read it. unfortunately most of the explanations I find are either way above my head, using terminology I don't really understand, or are way too simple, explaining only about the primary timings.

 

also note, when it says auto, I assume that it's at the default value, to the left of the selection box, but I'm not 100% sure it is. my motherboard tries to be very "hands off" and when I initially tried to run my RAM at 2133Mhz and not tweaking anything else, it automatically set my timings to something atrocious. like 14-16-16-30 (not exact timings BTW, just the hazy memory of what I remember)

 

My Timings:

Spoiler

Sorry for the low-quality pics. Obviously I can't screenshot in BIOS

0519172016a.jpg

0519171932a.jpg

0519171933.jpg

 

QUOTE/TAG ME WHEN REPLYING

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MageTank do you have any info on the VTTDDR voltage? As far as I've heard, you want it at half the DRAM voltage (but not over 0.75V), but that's about it. Would be great to learn more about it if there is anything important to know :)

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4 hours ago, steffeeh said:

MageTank do you have any info on the VTTDDR voltage? As far as I've heard, you want it at half the DRAM voltage (but not over 0.75V), but that's about it. Would be great to learn more about it if there is anything important to know :)

That is exactly what I have heard over the years. AMD's engineers also corroborated this information recently on Zen (and we used the same rule back on older DDR3 Intel platforms). Here is a video from an AMD engineer explaining memory overclocking:

 

At around the 11:30 mark, you can see DRAM VREF Voltage, which is AMD's version of VTTDDR. 90% of what this guy says is absolutely on the mark. I just have disagreements with his stability testing methodology (which as I said in my guide, everyone has their own way of doing things). I may contact Blunty and see if he will allow me to use his video here for the Ryzen part of the guide, until I can get my hands on Ryzen myself. If anything, I will buy a cheapo 4c Ryzen SKU and OC memory with that. Besides, it will also provide some data as to how well the budget Ryzen SKU's scale with memory overclocking. A 2-in-1 win.

My (incomplete) memory overclocking guide: 

 

Does memory speed impact gaming performance? Click here to find out!

On 1/2/2017 at 9:32 PM, MageTank said:

Sometimes, we all need a little inspiration.

 

 

 

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Thanks for the vid. Nice to know I'm not the only one curious about it. The only difference is that he said to not go above 0.9V, but I guess it's specific for the AMD platform.

 

Anyway, I wonder what I can expect from attempting memory overclocking on the X99 platform (XMP 2400MHz 14-16-16-31), as this chipset is known to have RAM compability issues that is especially present when you've done heavier overclocking and/or filled most RAM slots - basically 2800-3000MHz may normally not post (or only post with one of the sticks) since the system config doesn't seem to like it, even if it's an XMP profile.

I've even told several people on Z170 (this chipset also having this compability issue sometimes, but much lighter) who can't make their XMP with 3000MHz post, to instead go higher to 3200MHz and most of them managed to get things stable that way.

I have myself not been able in the past to get the BIOS to post beyond 2666MHz (except 2800MHz that only posted with one of the two sticks, but that's not stable).

Have you heard of any people being able to make it stable on X99 despite this, and how they managed?

 

Also, you mention that one should loosen the primary timings (among other things) to make an overclock stable if it's not stable at first - but when do the other timings come in (secondary, tertiary, etc)? Or are they only tweaked to improve performance even further, not necessarily related to the RAM speed stability/compability like the primary timings are?

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Don't forget to invest in an Intel Tuning Plan if you're going to overvolt your K/X CPU

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2 hours ago, steffeeh said:

Thanks for the vid. Nice to know I'm not the only one curious about it. The only difference is that he said to not go above 0.9V, but I guess it's specific for the AMD platform.

 

Anyway, I wonder what I can expect from attempting memory overclocking on the X99 platform (XMP 2400MHz 14-16-16-31), as this chipset is known to have RAM compability issues that is especially present when you've done heavier overclocking and/or filled most RAM slots - basically 2800-3000MHz may normally not post (or only post with one of the sticks) since the system config doesn't seem to like it, even if it's an XMP profile.

I've even told several people on Z170 (this chipset also having this compability issue sometimes, but much lighter) who can't make their XMP with 3000MHz post, to instead go higher to 3200MHz and most of them managed to get things stable that way.

I have myself not been able in the past to get the BIOS to post beyond 2666MHz (except 2800MHz that only posted with one of the two sticks, but that's not stable).

Have you heard of any people being able to make it stable on X99 despite this, and how they managed?

 

Also, you mention that one should loosen the primary timings (among other things) to make an overclock stable if it's not stable at first - but when do the other timings come in (secondary, tertiary, etc)? Or are they only tweaked to improve performance even further, not necessarily related to the RAM speed stability/compability like the primary timings are?

Okay, X99 is tricky because it hosts two different architectures. Haswell-E's IMC is complete trash, and has serious issues overclocking ram with 2DPC, and doesn't like multi-rank kits much at all. Broadwell-E's IMC fixed a lot of this issue, and allowed people to reach 3000-3200 stable, but not much higher than this. If you want the best chance to hit higher memory clock speeds, run 1DPC and use single rank kits. Looking at your sig, it seems you've already done that.

 

As for the second part of your post, tertiary timings are related to ram speed, very much so. Understand, primary timings and frequency dictate the window your ram operates in. If you have a frequency of 3000, you have a peak theoretical memory bandwidth of 48GB/s in dual channel. That is the window, while tertiary timings dictate efficiency. That is to say, how much of that 48GB/s you will actually get when using your ram. With poorly trained tertiary timings, you might only be able to get 80% of that bandwidth, meaning you cap out at about 38.4GB/s. With extremely tight tertiary timings, I (along with others) have achieved upwards of 98% write efficiency and 95% read efficiency. Meaning we achieve almost all of our peak theoretical memory bandwidth. A 3000 kit at 95% efficiency will always almost as fast as a 3600 kit at 80% efficiency. 45.6GB/s vs 46GB/s. 

 

Tertiary timings also have a far greater impact on stability. tRDWR specifically governs your AVX heat, and can make unstable CPU overclocks stable, while the rest of your tertiary timings are capable of reducing stress off of your IMC when running 2DPC or multi-rank kits. Part of the reason why Ryzen has huge memory compatibility issues, is because these timings are off limits to enthusiasts to help stabilize it. I would recommend not compromising on primary timings until you hit a frequency wall. Once you hit that frequency wall, test how much latency you are sacrificing (if any) to achieve a higher clock speed with looser primary timings. If you can get a considerable gain in clock speed, without sacrificing latency at all, it's a good trade. If you have to sacrifice latency, even by a little bit, it's a bad trade, and should not be made. 

My (incomplete) memory overclocking guide: 

 

Does memory speed impact gaming performance? Click here to find out!

On 1/2/2017 at 9:32 PM, MageTank said:

Sometimes, we all need a little inspiration.

 

 

 

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Interesting read. I didn't bother with the timings on mine as I believe it wouldn't have significant impact on general performance and just set the frequency to 2133MHz and voltage to 1.7v from default 1600MHz 1.5v and it has been stable ever since I got these DDR3 chips. Going from 1600MHz to 2133MHz helped at minumum FPS, which is great. Hopefully once I upgrade to Ryzen I can just do the same, buy a cheap 2400MHz kit and bump it up to 3000MHz at 1.4v-1.6v and call it a day.

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Slightly off topic, but how do I know if I run single rank and 1DPC?

 

This is my exact RAM kit:

http://www.corsair.com/en-eu/vengeance-lpx-16gb-2x8gb-ddr4-dram-2400mhz-c14-memory-kit-black-cmk16gx4m2a2400c14

 

EDIT: Finally found some basic info on DPC, and I assume you mean by 1DPC that my two RAM sticks are properly running in dual channel mode, instead of single channel per stick?

Asus X99-A w/ BIOS 3402 | Intel i7 5820k OC @4.4GHz 1.28V w/ Noctua NH-U14S | 16GB Corsair Vengeance DDR4 OC @2666MHz 12-14-14-28 | Asus Geforce GTX970 STRIX OC | EVGA 750 G2 750W | Samsung 850 Evo 1 TB | Windows 10 64-bit | Be-Quiet Silent Base 800 w/ Silent Wings | 2x Dell U2414H OC @72Hz w/ Display Port

 

Don't forget to invest in an Intel Tuning Plan if you're going to overvolt your K/X CPU

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