Mixing different RAM timings

[redespace]

Hey guys,

 

I currently have 2x8GB sticks from SK Hynix (it came with the pre-build), which are 3200Mhz (timings: 22-22-22) @1.2V . Since those timings are pretty bad, and I am running a 5900x CPU, I was looking to buy G.Skill's F4-3600C16D-16GTZNC (timings:16-19-19) @1.35V . I am guessing the only option to mix those would be to try and overclock the Hynix sticks, but not sure if that would even work.

Most probably all 4 sticks in that case would underclock to 3200MHz and those horrible timings right?

[Blackjack1336]

3 minutes ago, redespace said:

Hey guys,

 

I currently have 2x8GB sticks from SK Hynix (it came with the pre-build), which are 3200Mhz (timings: 22-22-22) @1.2V . Since those timings are pretty bad, and I am running a 5900x CPU, I was looking to buy G.Skill's F4-3600C16D-16GTZNC (timings:16-19-19) @1.35V . I am guessing the only option to mix those would be to try and overclock the Hynix sticks, but not sure if that would even work.

Most probably all 4 sticks in that case would underclock to 3200MHz and those horrible timings right?

I never heard that one is able to go over the rated mhz of a RAM stick without major stability loss. You could always lock your speeds to the lowest stick you have. Generally it’s not recommended. You should sell your sticks and get a solid 3600mhz ddr4 Kit 

[Fasauceome]

17 minutes ago, Blackjack1336 said:

never heard that one is able to go over the rated mhz of a RAM stick without major stability loss.

Well typically that would be done via an OC

 

Speaking of, @redespaceyou should see if you can lower your timings on your memory via an overclock. If you could get your 3200 kit down to something like CL17 or 16, chances are the other memory would be able to match that. As for trying to get to 3600MHz, you likely would not enable that via XMP. While sometimes I have seen motherboards do this, it's an exception that a board will OC the slower memory to match the faster.

[Han2K]

In the best case scenario the RAM would work at the same clocks and timings of the lowest one of the sticks. The motherboard will set by default DRAM voltage at 1.2v.

If you are lucky the PC will POST. A little more luck and Windows will boot. Then you need even more luck to achieve a stable system.

Anyway, it won't probably POST: some issue from MOBO/BIOS , CPU DRAM Host Controller or very much probable: XMP failure when trying to apply the profile. 

 

To sum up, forget the idea, you are buying problems. 

 

 

 

[RONOTHAN##]

1 hour ago, Blackjack1336 said:

I never heard that one is able to go over the rated mhz of a RAM stick without major stability loss.

I've ran a kit of 3600MHz CL17 at 4400MHz CL15 without a single stability issue. Granted, that was specifically looking for memory to OC, but this isn't something that's super uncommon and if you have some idea of what you're doing you can get some serious performance improvements out of it. 

 

Anyway, @redespace this isn't a good idea if your goal is to run 32GB of RAM at 3600MHz. Memory OC is tough enough, mixed memory OC is even harder. You will likely get 2 different memory ICs, and different memory ICs have different timing and termination requirements. You might be able to get them to 3600MHz individually, but together I'd be shocked if you managed to get it stable without a ton of fine tunings and loosening out the timings on both kits. 

 

I'm not saying it's impossible, I have done it (granted that was with a ton of time and effort and I wouldn't wish it on my worst enemy), but if this is your goal you really are better off flipping your current kit and just buying a 2x16GB kit, aiming for something dual rank possibly (either that or going for single rank B die and just overclocking it a bit, 3800MHz CL14 is the timings you should aim for on a 5900X, settling for 3800MHz CL16 or 3733MHz CL16. 

[redespace]

10 hours ago, RONOTHAN## said:

I've ran a kit of 3600MHz CL17 at 4400MHz CL15 without a single stability issue. Granted, that was specifically looking for memory to OC, but this isn't something that's super uncommon and if you have some idea of what you're doing you can get some serious performance improvements out of it. 

 

Anyway, @redespace this isn't a good idea if your goal is to run 32GB of RAM at 3600MHz. Memory OC is tough enough, mixed memory OC is even harder. You will likely get 2 different memory ICs, and different memory ICs have different timing and termination requirements. You might be able to get them to 3600MHz individually, but together I'd be shocked if you managed to get it stable without a ton of fine tunings and loosening out the timings on both kits. 

 

I'm not saying it's impossible, I have done it (granted that was with a ton of time and effort and I wouldn't wish it on my worst enemy), but if this is your goal you really are better off flipping your current kit and just buying a 2x16GB kit, aiming for something dual rank possibly (either that or going for single rank B die and just overclocking it a bit, 3800MHz CL14 is the timings you should aim for on a 5900X, settling for 3800MHz CL16 or 3733MHz CL16. 

Thank you guys very much for the advice! Yeah, most probably I will just sell the existing 16GB kit and buy the G.Skill ones at 3600MHz CL16. I will try to see if I can get to OC it, but since I've never done it before and my primary use is gaming, not sure that small increase in MHz would actually help get more fps

[RONOTHAN##]

21 minutes ago, redespace said:

Thank you guys very much for the advice! Yeah, most probably I will just sell the existing 16GB kit and buy the G.Skill ones at 3600MHz CL16. I will try to see if I can get to OC it, but since I've never done it before and my primary use is gaming, not sure that small increase in MHz would actually help get more fps

If you want to get into RAM OC, you should really be more looking at the specific kit and memory bin, the three big ones that are easy to target are Micron Rev.E 8Gb, Micron Rev.B 16Gb, and Samsung B die 8Gb. The Micron kits are easy, Rev.B is better than Rev.E for overclocking, and they're in 2x8GB and 2x16GB kits respectively. Samsung B die is the absolute best on DDR4 currently it's about the same price per gigabyte as Rev.E, but it's a little more weird to shop for. If you want B die new, you need to look for kits 3200MHz and higher with flat/mostly flat primary timings (14-14-14, 14-15-15, 17-18-18, 19-19-19, etc., you won't find B die in a CL20 or higher kit though), currently the cheapest way to get it (at least in the US) is Patriot Viper Steel 4000MHz CL19-19-19 kits, those should do 3800MHz CL16 without too much of a fight. A 4x8GB setup with Patriot Viper Steels (good bin, not 3200MHz CL16 or 3600MHz CL18) would be an awesome setup and is effectively the fastest memory you can have on Ryzen since it would be effectively dual rank B die (dual rank is kinda like adding 400MHz to the RAM given the same timings in terms of performance), though it would be a bit expensive and a 3600MHz CL16-19-19 bin might just make more sense. 

 

It does depend on the game how much RAM OC will help. Some games do benefit a fair bit from tightened RAM and maxed out infinity fabric, others couldn't care less. Look up some games so you know for certain, but I wouldn't assume it's nothing (in 3DMark CPU tests I know my RAM OC, dual rank 3800MHz CL14-13-13-21 B die with dialed in subtimings with a 5900X, gets something like an extra 1000 points in Time Spy Extreme CPU score over 3600MHz CL16 XMP settings, 10% faster)

[redespace]

21 minutes ago, RONOTHAN## said:

If you want to get into RAM OC, you should really be more looking at the specific kit and memory bin, the three big ones that are easy to target are Micron Rev.E 8Gb, Micron Rev.B 16Gb, and Samsung B die 8Gb. The Micron kits are easy, Rev.B is better than Rev.E for overclocking, and they're in 2x8GB and 2x16GB kits respectively. Samsung B die is the absolute best on DDR4 currently it's about the same price per gigabyte as Rev.E, but it's a little more weird to shop for. If you want B die new, you need to look for kits 3200MHz and higher with flat/mostly flat primary timings (14-14-14, 14-15-15, 17-18-18, 19-19-19, etc., you won't find B die in a CL20 or higher kit though), currently the cheapest way to get it (at least in the US) is Patriot Viper Steel 4000MHz CL19-19-19 kits, those should do 3800MHz CL16 without too much of a fight. A 4x8GB setup with Patriot Viper Steels (good bin, not 3200MHz CL16 or 3600MHz CL18) would be an awesome setup and is effectively the fastest memory you can have on Ryzen since it would be effectively dual rank B die (dual rank is kinda like adding 400MHz to the RAM given the same timings in terms of performance), though it would be a bit expensive and a 3600MHz CL16-19-19 bin might just make more sense. 

 

It does depend on the game how much RAM OC will help. Some games do benefit a fair bit from tightened RAM and maxed out infinity fabric, others couldn't care less. Look up some games so you know for certain, but I wouldn't assume it's nothing (in 3DMark CPU tests I know my RAM OC, dual rank 3800MHz CL14-13-13-21 B die with dialed in subtimings with a 5900X, gets something like an extra 1000 points in Time Spy Extreme CPU score over 3600MHz CL16 XMP settings, 10% faster)

Wow! That's some nice OC timings you got there. I wouldn't have thought that you could get 10% increase only from timings... Great job!

[RONOTHAN##]

16 minutes ago, redespace said:

Wow! That's some nice OC timings you got there. I wouldn't have thought that you could get 10% increase only from timings... Great job!

Granted, there are applications like Cinebench that couldn't care less what the memory settings are, so a 10% increase is about the max it can be. Still though, it's something to think about.