Which RAM to choose for AMD 7950X3D and keep a 1:1 ratio

[curtisdodo]

Hello,

I bought my configuration :

Noctua NH-D15
RYZEN 9 7950X3D
X670E-F GAMING ASUS STRIX
RTX 4090

I'm looking for 64GB of the best performing RAM in low profile (for the NH-D15), in two sticks so 2x32.
Ideally non-RGB and EXPO certified.

But it is important to have a 1:1 ratio between the Memory Controller (UCLK) and the Memory Clock (MCLK).

In my country (France) very few dealers have 6000Mhz CL30.

I have seen these references:
KF560C36BBEK2-64 - 36-38-38
CMK64GX5M2B6000Z40 - 40 40 40 77

I read a comment that if you go from 2x16 to 6000 you have to go to 2x32 5600 to keep 1:1, is this true?

Please help me.

 

[dgianstefani]

You can't do 1:1.

Get 6000 EXPO, the rest doesn't matter.

 

[GerKNG]

6000 is the new 3600.
a small handful of chips can do 6200 on a decent board.
if you want 64GB you often can get away with looser timings at 6000.

 

[curtisdodo]

Ok thanks, is there a difference between 6000Mhz CL40 vs CL36?

 

[dgianstefani]

CL36 is slightly faster, but AMD latency is bad anyway due to chiplets so it won't really make a difference.

 

[curtisdodo]

In your opinion, is it better to have 2x16GB in 6000Mhz CL30 (30 38 38 96) or 2x32GB in 6000Mhz CL36 38 38?

 

[P4-630]

In your opinion, is it better to have 2x16GB in 6000Mhz CL30 (30 38 38 96) or 2x32GB in 6000Mhz CL36 38 38?

Depends on the price I guess, or if you really need 64GB.

 

[R-T-B]

You can't do 1:1.

Get 6000 EXPO, the rest doesn't matter.

I'm doing 1:1 with my kit, but at 5600. Can't say it's bothered me much.

Edit: Not x3d though.

 

[Why_Me]

Asus board + X3D cpu + EXPO. This has all the makings of a great thread ^^

 

[Chrispy_]

Asus board + X3D cpu + EXPO. This has all the makings of a great thread ^^

Heheh, yeah.
I'd be aiming for 5600 kits, myself. Getting 64GB stable at 6000 isn't impossible, but it will probably give you a headache trying RAM timings.
Just because something says EXPO and is AMD-certified doesn't mean your particular board/processor can handle it. Anything above DDR5-5200 is overclocking and down to the silicon lottery.
2x32GB @ 5600 has good odds of working with the EXPO presets. I don't have enough experience with AM5 yet, but 64GB of 6000 at stock timings seems unlikely.

 

[curtisdodo]

So for the record, I've been looking into the kit I want, which is : F5-6000J3040G32GX2-RS5K is DDR5 6000, CL 30 2X32Gb XMP.

Several things are bothering me.

Firstly I see that all the B650 or X670 from MSI they support this F5-6000J3040G32GX2-RS5K RAM with XMP profile so why not my ASUS?

Then I notice one thing. On the list of RAMs compatible with my motherboard I see that an exactly similar version (same chip, same voltage, same timing, same frequency) is compatible but RGB and it is labelled EXPO. So why wouldn't the RAM I chose be compatible?

On the screens, the first one the RAM I want, compatible with a motherboard taken at random in B650 MSI.
On the second screen, an identical model but EXPO certified.

 

[tabascosauz]

So for the record, I've been looking into the kit I want, which is : F5-6000J3040G32GX2-RS5K is DDR5 6000, CL 30 2X32Gb XMP.

Several things are bothering me.

Firstly I see that all the B650 or X670 from MSI they support this F5-6000J3040G32GX2-RS5K RAM with XMP profile so why not my ASUS?

Then I notice one thing. On the list of RAMs compatible with my motherboard I see that an exactly similar version (same chip, same voltage, same timing, same frequency) is compatible but RGB and it is labelled EXPO. So why wouldn't the RAM I chose be compatible?

On the screens, the first one the RAM I want, compatible with a motherboard taken at random in B650 MSI.
On the second screen, an identical model but EXPO certified.

Because different boards have different memory topologies that result in different memory performance and general capability when it comes to max achievable freq?

QVL doesn't mean everything - they only put on the list what they test. Maybe they just didn't have that exact kit on their hands. There's a smorgasbord of Hynix A/M kits at 6000 from various vendors; if your QVL already lists support for numerous other comparable Hynix kits, then I don't see what's stopping you from getting the CL30 Hynix kit.

Generally on AM5 neither your board nor Hynix kit is going to be the limiting factor to the max speed you can run auto:1:1 - your CPU will be, specifically, getting UCLK (mem controller freq) above 3000.

QVL also doesn't say anything about whether the kit is doable at 1:1 or 1:2. Technically, running it 1500MHz UCLK would still be "supporting" the 6000CL30 kit.............I'm not familiar whether if Raphael's memory controller suffers from dual rank to the point where a 2x32GB kit can't do 6000 1:1. Hence why AM4 boards all advertise support for the ultra high end Micron/Hynix 5100/5333 kits - no way you would run them as a daily, but they do "work" at half UMC speed.

 

[curtisdodo]

I have confirmation that with two 2x32 sticks you have to use gear2. so 2:1

I am hesitating between the F5-5600J2834F32GX2-RS5K or the F5-6000J3038F16GX2-FX5

So 2x16 6000CL30 or 2x32 5600CL28.

Both Hynix chips

What do you recommend?

 

[tabascosauz]

I have confirmation that with two 2x32 sticks you have to use gear2. so 2:1

I am hesitating between the F5-5600J2834F32GX2-RS5K or the F5-6000J3038F16GX2-FX5

So 2x16 6000CL30 or 2x32 5600CL28.

Both Hynix chips

What do you recommend?

Depends on how hungry you are for more RAM. If you need 64GB, no 32GB kit will do the job no matter how fast it is.

Sub-6000 on AM5 isn't a big deal if you are willing to put in the work.

 

[ir_cow]

2x32GB DDR5-6000 @ FCLK 2000MHz : 1 : 1 works for me on all MBs so far. A lot default to 2:1 and some need to up the SoC voltage if you want 1:1 to work.

 

[The Von Matrices]

Heheh, yeah.
I'd be aiming for 5600 kits, myself. Getting 64GB stable at 6000 isn't impossible, but it will probably give you a headache trying RAM timings.
Just because something says EXPO and is AMD-certified doesn't mean your particular board/processor can handle it. Anything above DDR5-5200 is overclocking and down to the silicon lottery.
2x32GB @ 5600 has good odds of working with the EXPO presets. I don't have enough experience with AM5 yet, but 64GB of 6000 at stock timings seems unlikely.

I got my 64GB kit working on my 7950X3D at DDR5-6000 CL30, but I spent a lot of time getting this stable, and this is the tightest I can get despite having a DDR5-6400 memory kit. DDR5-6200 will not boot no matter how much voltage or how loose of timings I use. In contrast, DDR5-5600 was a piece of cake to get working and works fine at stock voltages. An EXPO kit for DDR5-6000 is probably the best solution, but I didn't buy one because the latencies of the EXPO kits were a lot higher than the Intel kits and I was willing to put in the extra effort.

 

[curtisdodo]

That's the problem, I don't want to fix the tensions myself, I just want to activate the ready-made profile and make it work.
In 64GB, there is hardly any kit in DDR5 with latencies below 36. Otherwise it's all XMP.

 

[ir_cow]

That's the problem, I don't want to fix the tensions myself, I just want to activate the ready-made profile and make it work.
In 64GB, there is hardly any kit in DDR5 with latencies below 36. Otherwise it's all XMP.

I've been having a hard time getting dual-rank kits to boot below CAS36. Idk what that is about. Probably just a CPU IMC thing. Single-rank works down to CAS 28 (lowest I've tried).

 

[The Von Matrices]

I've been having a hard time getting dual-rank kits to boot below CAS36. Idk what that is about. Probably just a CPU IMC thing. Single-rank works down to CAS 28 (lowest I've tried).

It took a lot of fiddling with 2nd and 3rd level subtimings; I definitely had to do a lot of learning. There are other forums online that have sample configurations that work with these high speeds and low latencies.

 

[curtisdodo]

So I'm still not making any progress. If I want a ready to use kit without modifying anything myself that works in 1:1, should I start with the 2X32 5600CL28 in XMP?
Is lowering the frequency a bit from 6000 to 5600 but lowering the latency and going to 64GB I gain in performance?

32GB 6000CL30 < 64GB 5600C28?

 

[The Von Matrices]

The first thing you need to determine is whether your workloads need more than 32GB of memory. Your system will not be any faster with 64GB of memory if you never use more than 32GB.

 

[ir_cow]

So I'm still not making any progress. If I want a ready to use kit without modifying anything myself that works in 1:1, should I start with the 2X32 5600CL28 in XMP?
Is lowering the frequency a bit from 6000 to 5600 but lowering the latency and going to 64GB I gain in performance?

32GB 6000CL30 < 64GB 5600C28?

If you want 64GB, get 5600 for hassle free experience. Otherwise play the game of luck with 6000+

 

[R-T-B]

If you want 64GB, get 5600 for hassle free experience. Otherwise play the game of luck with 6000+

This was my philosophy. Go with it. It will be pain free.

If you don't need 64GBs, likewise, the decision for 32GBs of faster ram should be easy.

 

[AleXXX666]

This was my philosophy. Go with it. It will be pain free.

If you don't need 64GBs, likewise, the decision for 32GBs of faster ram should be easy.

even if you don't need 64 GB, there is also one factor: PRICE. If getting 64 GB "slower" memory is CHEAPER than 32 GB "ULTRA-FAST-OC-EXTREME-NITRO-RAM", then one should be dumb like me to overpay. I overpaid for 16 GB "faster" DDR4 vs "i had" 24 GB of "slouch", and for 32 GB for the price I could EZ have found "a little slower" 64 GB.

 

[Gungar]

Asus board + X3D cpu + EXPO. This has all the makings of a great thread ^^

I have that combo and it works just fine.