four sticks, no xmp cpu's fault?

john terragon · 1 Dec 2021 at 08:29

Hi.
I've got a 5950x and 4 sticks of DDR4 with 3600 xmp frequency. If I install two of them at a time then I can use the xmp profile and memtest86 gives zero errors. If I install all of them then memtest86 gives errors at 3600. But all four at 2666 are fine with memtest86.
I think I've read somewhere than when this happen the culprit is the memory controller on the cpu.
Is that right?
If that's the case then it would be useless to try to change the 4 dimms. Any 4 dimms of any model would give the same problems at 3600 right?

Also, the tests have been conducted with pbo enabled (nothing crazy, just the standard settings). Is pbo causing this? You know, like in certain intel cpus that when you overclocked them you lost the possibility of overclocking the RAM too?

Thanks

Minstadave · 1 Dec 2021 at 08:31

What size are the sticks?

john terragon · 1 Dec 2021 at 08:41

32 gb each

alec · 1 Dec 2021 at 08:42

PBO is unlikely to cause this
It is down to memory controller or motherboard. Most likely can be remedied by playing around with vsoc, vddp, vddg voltages. Not an expert, remember seeing a few topics from Zen 2 days

Do a quick test and bump primary timings by 2, does that fix errors? For example from 16-18-18 to 18-20-20

32GBx4? Wow, you are asking a lot from that poor memory controller

john terragon · 1 Dec 2021 at 08:52

OK. I'll try it.
To find the maximum working frequency can I just keep the timings from the 3600 xmp profile and then lower the frequency until I get no errors? (and maybe later, when I have a max frequency, tight up the timings?).

alec · 1 Dec 2021 at 10:57

john terragon said:
OK. I'll try it.
To find the maximum working frequency can I just keep the timings from the 3600 xmp profile and then lower the frequency until I get no errors? (and maybe later, when I have a max frequency, tight up the timings?).

yea, thats exactly how you should go for it
2T command rate may be necessary for 4x dual rank sticks, altho so far 1T and GDM on has always worked for me

john terragon · 1 Dec 2021 at 11:26

alec said:
yea, thats exactly how you should go for it
2T command rate may be necessary for 4x dual rank sticks, altho so far 1T and GDM on has always worked for me

Those are all greek to me

but I'll look them up.
Things look volatile though because at 3200 memtest86 started to show errors after 50% while on 3000 it failed almost immediately.

Minstadave · 1 Dec 2021 at 11:31

The problem is trying to run 4 dual rank sticks at high speeds on X570 doesn't work well. The memory controller and the board have an impact on the max speed possible.

john terragon · 1 Dec 2021 at 11:37

Minstadave said:
The problem is trying to run 4 dual rank sticks at high speeds on X570 doesn't work well. The memory controller and the board have an impact on the max speed possible.

Yes.
However I have another 5950x on a very similar board, msi ace x570, and in that case another 128gb 4 sticks, this time with 3200 xmp, work wihtout a hitch.
So, maybe I've been unlucky with the second 5950x and the msi ace x570s max, which actually should be better with memory than the old msi ace. So maybe the culprit is the new 5950x.

john terragon · 3 Dec 2021 at 17:30

Just to close the topic.
I've changed the four sticks of DDR4:
before: patriot 128GB 3600 Mhz 18 22 22 42
now: kingston 128GB 3600 Mhz 18 22 22 39

Before the only stable frequency was 2666
Now, with the new ones it's rock solid at 3600 without changing anything from the xmp profile.

So we have two cases:

1) If the culprit for the instability was the cpu+mb because 128GB dual rank at 3600 was asking too much of them then I don't understand why now with the same speed and size cpu+mb are suddenly able to handle them.

2) On the other hand, if the culprit was the first kit of memory then I don't understand how ca nthey work at 3600 one pair at a time but then they become unstable when all four are installed (having excluded that cpu+mb can't handle them).

It's a mistery to me.

Lukas+ · 18 Sep 2022 at 05:58

Hi! Sorry if I re-open this old topic, but you seem expert about and I'm going to buy an Msi Meg X570S Ace Max and I'll need an advice. So, for 64gb of ram, what should I buy? The internet lacks of informations about this motherboard; I though a 4x16, but single side, double side or dual rank? What about the frequencies? 3600 is ok?
It's 128GB better? And, by that way, 4x32GB of... single? Double? Dual?

I hope to read a your answer soon!
Thanks for your time and patience.
Bye