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After seeing Linus get corrected by Buildzoid of AHOC (Actual Hardcore Over-Clocking) channel.

I thought I would make a simple guide to help those who need a reference guide for RAM / Memory Timings.

 

For those who need a Look Up Table on how to decipher your RAM timings and what's the true speed behind those Clock Cycle numbers listed on your (DIMM AKA Memory Module)'s sticker.

I made a "Home Made" new version of the RAM Timing table and color-coded the RAM speeds that are listed in (ns = Nano-Seconds).

Here's the Image Version:

1925514995_RAMTimings.thumb.png.a817e92e115dd91506e1b36ff65b8f9e.png

 

Here's the original Excel Spread Sheet file for those who want it: RAM Timings.xls

 

Here's a sample of the Sticker that shows yoru RAM timings, you can usually either find a picture of the RAM Timing Stickers online for your Memory Module of choice or it'll be listed in the product listing.

1938754958_DIMMTimingLabelSticker.png.3233aca48c6965fae8b05b9dfc8d69b1.png

 

Wikipedia also has a good simple explanation for Memory Timing / RAM Timing.

The Wikipedia article will explain what each of the RAM Memory Timings {CL - tRCD - tRP - tRAS - CR = Units are measured in (Clock Cycle's)} mean.

NOTE:  CR = Command Rate:  Usually is either 1T or 2T.

1T is generally preferable & faster, but 2T is acceptable. It's a timing I wouldn't worry that much about in the grand scheme of things compared to the other timings.

 

If you have any other questions, I'll do my best to help within reason.

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Does Linus even bench? 😄

 

I doubt it..🤑

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6 minutes ago, freeagent said:

Does Linus even bench? 😄

 

I doubt it..🤑

He doesn't need to, that's why he has staff to do the bench work for him.

 

There's the reason he's "The Boss" of Linus Tech Tips (Along with Yvonne) & is the "Face that Runs the Place".

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1 hour ago, freeagent said:

Does Linus even bench? 😄

 

I doubt it..🤑

No, not competitively. And pretty sure none of the staff either. 

 

There are a couple or so LTT HWBot bench teams, none of which are official.

 

Also, there will be no promotion for hwbot from LTT because it's not going to be profitable to LTT. 

 

TlDr - nope. His employees... nope.

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3 hours ago, Kamen Rider Blade said:

He doesn't need to, that's why he has staff to do the bench work for him.

 

There's the reason he's "The Boss" of Linus Tech Tips (Along with Yvonne) & is the "Face that Runs the Place".

It was a joke, lighten up..

AMD R7 5800X3D | Thermalright Phantom Spirit 120 EVO, 1x T30

Asus Crosshair VIII Dark Hero | 32GB G.Skill Trident Z @ 3733C14

Zotac 4070 Ti Trinity OC @ 3060/1495 | WD SN850, SN850X, SN770

Seasonic Vertex GX-1000 | Fractal Torrent Compact RGB, Many CFM's

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Kudos! That's really cool to see at a glance. I have a few questions, though:

  • Is the CCT column the CAS latency?
  • Is the number across the MT and CCT values the "true speed"?

Thanks again for the chart!

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31 minutes ago, BookofNeat said:

Kudos! That's really cool to see at a glance. I have a few questions, though:

  • Is the CCT column the CAS latency?
  • Is the number across the MT and CCT values the "true speed"?

Thanks again for the chart!

The CCT is general Clock Cycles of the I/O Bus between the RAM Module & Memory Controller.

It can be applied to all these RAM Memory Timings {CL - tRCD - tRP - tRAS} & some of the hidden memory timings inside the BIOS under the advanced menu; but that's a deeper discussion for another thread and another time.

 

The only thing Clock Cycles can't really apply to is CR = Command Rate

Command Rate has historically been either 1T or 2T which stands for waiting 1 Clock Cycle for Chip Select to complete it's selection, or 2 Clock Cycles.

Obviously 1 Clock Cycle is faster than 2 Clock Cycles, but due to timing reasons, many people can get by with 2 if need be.

 

The numbers you reference between Clock Cycles listed on the Sticker & MegaTransfers is the "True Speed" in (ns = Nano-Seconds).

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Is there going to be an extended version of this chart in the future?

 

Only curious because I can select up to 13333 frequency (not that I'll ever reach that lol)

 

image.thumb.jpeg.b728a573e78f2a676efa03d9a1f0a227.jpeg

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54 minutes ago, Guest 5150 said:

Is there going to be an extended version of this chart in the future?

 

Only curious because I can select up to 13333 frequency (not that I'll ever reach that lol)

 

image.thumb.jpeg.b728a573e78f2a676efa03d9a1f0a227.jpeg

When they start making DDR5 RAM Modules up to those speeds, I'll extend the list as necessary.

 

Until then, it should be fine until we start seeing speeds extend past the current maximum.

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2 minutes ago, Kamen Rider Blade said:

Ack, sidways neck cramp; next time film it so that I don't have to bend my neck & head 90° to read the sticker.

That is filmed MP4 2 second duration and it's right side up on my screen 🤷‍♂️

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On 7/18/2022 at 10:14 PM, Kamen Rider Blade said:

The CCT is general Clock Cycles of the I/O Bus between the RAM Module & Memory Controller.

It can be applied to all these RAM Memory Timings {CL - tRCD - tRP - tRAS} & some of the hidden memory timings inside the BIOS under the advanced menu; but that's a deeper discussion for another thread and another time.

 

The only thing Clock Cycles can't really apply to is CR = Command Rate

Command Rate has historically been either 1T or 2T which stands for waiting 1 Clock Cycle for Chip Select to complete it's selection, or 2 Clock Cycles.

Obviously 1 Clock Cycle is faster than 2 Clock Cycles, but due to timing reasons, many people can get by with 2 if need be.

 

The numbers you reference between Clock Cycles listed on the Sticker & MegaTransfers is the "True Speed" in (ns = Nano-Seconds).

So, if I understand this, it means that CCT is the speed/delay of information moving from RAM and the controller and the "True Speed" is MHz/CAS Latency or MegaTransfers/Clock Cycles. So if I had a set of RAM rated for 3000MHz at CL15, then the "True Speed" would be 10ns response/delay time?

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5 hours ago, BookofNeat said:

So, if I understand this, it means that CCT is the speed/delay of information moving from RAM and the controller and the "True Speed" is MHz/CAS Latency or MegaTransfers/Clock Cycles. So if I had a set of RAM rated for 3000MHz at CL15, then the "True Speed" would be 10ns response/delay time?

You sort of understand it; you're applying the "True Speed" to everything when it's not supposed to.

It really only applies to that specific Timing listed on the Sticker Sheet.

 

The listed timings {CL - tRCD - tRP - tRAS} are all different actions related to fetching data from RAM.

These are the 4x most common that is commonly labeled by RAM Module Manufacturers/Vendors and the most popular, there are ALOT more hidden underneath the OC menu that isn't shown for brevity reasons.

 

 

CL = CAS Latency

That is only 1x of many subtimings for many actions.

 

Here's the Short Answer from Wikipedia:

Quote

Column Address Strobe (CAS) latency, or CL, is the delay in clock cycles between the READ command and the moment data is available. In asynchronous DRAM, the interval is specified in nanoseconds (absolute time). In synchronous DRAM, the interval is specified in clock cycles. Because the latency is dependent upon a number of clock ticks instead of absolute time, the actual time for an SDRAM module to respond to a CAS event might vary between uses of the same module if the clock rate differs

Remember, modern RAM is DDR# SDRAM which stands for (Double Data-Rate Synchronous DRAM).

So all actions are based off of # of Clock Cycles instead of (Absolute Time). You can also call it clock Ticks.

How fast you clock your memory, affects the base Time interval (length of time) between each Clock-Cycle or each Clock-Tick.

That's why you need a Look-Up table to translate it to True Latency based on common Time Units that we humans use.

 

 

Remember, CAS Latency:

Quote

The number of cycles between sending a column address to the memory and the beginning of the data in response. This is the number of cycles it takes to read the first bit of memory from a DRAM with the correct row already open. Unlike the other numbers, this is not a maximum, but an exact number that must be agreed on between the memory controller and the memory.

All this timing does is tell you the delay in ns (Nano-Seconds) to do this action to read the first bit of memory from DRAM.

 

 

TRCD = Row Address to Column Address Delay

Quote

The minimum number of clock cycles required between opening a row of memory and accessing columns within it. The time to read the first bit of memory from a DRAM without an active row is TRCD + CL

This sub timing could be different from CL, or the same; it depends on what the Memory manufacturer set in XMP, or you manually set it and test/validate that it works and is stable. This timing only affects how  long it takes to access the bit columns within the open row of memory.

 

 

There are countless timings like the ones listed above in your OC menu that affect different aspects of how RAM performs to fetch data.

Tuning it is a thankless job since it takes ALOT of testing to validate that it's stable.

 

 

5 hours ago, BookofNeat said:

So if I had a set of RAM rated for 3000MHz at CL15, then the "True Speed" would be 10ns response/delay time?

If your RAM module is set to a transfer speed of 3,000 MT/s and your CL Timing is set to 15, then the "True Speed" or how long it takes to complete that action would be exactly 10 ns. But that Timing value ONLY applies to CL.

 

If your TRCD value is set to 16, then it's "True Speed" would be 10.67 ns to perform TRCD.

 

Are you starting to get what I'm saying?

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5 minutes ago, Kamen Rider Blade said:

You sort of understand it; you're applying the "True Speed" to everything when it's not supposed to.

It really only applies to that specific Timing listed on the Sticker Sheet.

OOhhhh, I think I get it.

Thanks so much for answering!

Cheers! (ノ◕ヮ◕)ノ*:・゚✧

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