[SOLVED] DDR5 RAM not stable with XMP

[ediofs]

I have a newly built PC with DDR5 RAM and today I tried to enable XMP for the first time. Booting to Windows hasn't resulted in any issues so far. First pass of Memtest86+ was ok, but the second pass resulted in 4 errors. I'm not an OC expert at all, so I could use some direction as to what I should be looking at to get the RAM stable. I've read the stickied thread about troubleshooting RAM/XMP issues, but it's missing info on DDR5 so it doesn't quite help me. It's mostly about upping voltage, but I think 1.45V is already high for DDR5 (not sure though).

Most important thing for me is system stability, so I'm running CPU and GPU at stock, but running RAM at 67% of its advertised speed seems like a waste.

Specs:
Mobo: MSI MAG Z790 TOMAHAWK WIFI
CPU: Intel Core i9-13900K, stock settings except power limit (PL1 & PL2) set to 200W
RAM: Corsair Vengeance CMK32GX5M2X7200C34, DDR5 2x16GB 7200MHz 34-44-44-96

The RAM is not actively cooled (no fan directed at it). The case is cooled well.

CPU-Z specs, RAM voltages and Memtest86+ errors:

https://imgur.com/a/0PSnzhi

View: https://imgur.com/a/0PSnzhi

 

[SkyNetRising]

Most important thing for me is system stability, so I'm running CPU and GPU at stock, but running RAM at 67% of its advertised speed seems like a waste.

Reduce frequency to 7000mhz, retest.
If still getting errors, then reduce even further (in 200mhz steps).
At 5600mhz should be stable. Your result will probably be somewhere in between.

After that try reducing DRAM voltage. Try 1.35V.
Ideally, if you could lower to 1.2V.

 

[ediofs]

Reduce frequency to 7000mhz, retest.
If still getting errors, then reduce even further (in 200mhz steps).
At 5600mhz should be stable. Your result will probably be somewhere in between.

After that try reducing DRAM voltage. Try 1.35V.
Ideally, if you could lower to 1.2V.

Thanks, I'll try that and report back.

 

[Eximo]

7200 is bleeding edge, so no real guarantee that every CPU/Motherboard is going to run it without issues.

Take a look at some of Corsair's other slower kits and loosen the timings a bit.

I agree, I wouldn't want to daily drive 1.45 volts.

Long time ago I did that with early DDR3 at 1.65 volts (1.5 was the max then). Slowly died and the board started losing memory channels.

 

[ediofs]

Take a look at some of Corsair's other slower kits and loosen the timings a bit.

When you say loosen the timings do you mean just the frequency or also the CAS timings?

Edit:
Other question: when enabling XMP I get these settings:
DRAM Reference Clock: 100
CPU IMC DRAM Clock: Gear2
DRAM Frequency: 36

Should I just reduce the latter one or should I also look at the other 2 values?

 

[SkyNetRising]

When you say loosen the timings do you mean just the frequency or also the CAS timings?

Keep timings from XMP-7200 profile.
After you have lowered frequency and found stable settings, you can try also tightening timings.
But expect this to take a lot of time to test different timings. I'd be too lazy to do that.

 

[Eximo]

You can try 7200 with looser timings, sure. You are basically having to overclock your memory manually if you want to get anywhere close to 7200, just start trying things to get the most out of the kit you can.

CL34 is really low, and 7200 is really high. You might try 36-44-44-96

In looking at some DDR5 6600 you could try 32-39-39-76 at that speed, etc, only 1.4 volts there.

 

[Eximo]

Keep timings from XMP-7200 profile.
After you have lowered frequency and found stable settings, you can try also tightening timings.
But expect this to take a lot of time to test different timings. I'd be too lazy to do that.

Same, I don't usually go for the fastest memory.

I lucked out with my current 3200 kit in that it runs just fine at 3600.

Been looking at some DDR5 5600 kits with CL30, but still debating a build at all. (Not a high spec gaming, was thinking i3-12100F to replace my aging 4770k)

 

[ediofs]

As you can probably tell from me not tweaking my CPU and GPU, I'm definitely gonna be too lazy to optimize it to the max. There's just a rather big difference between 7200 and 4800

Could you take a quick look at the edit in my last comment?

Thanks for all the info, it's definitely useful to gain some insight from people who know something about this stuff

 

[Eximo]

Gear 1 means the memory controller is at the same speed as the RAM.
Gear 2 means half speed.

So 7200 Mt/s = 3600Mhz = 1800Mhz for Gear 2.

If you can manage 6600 or 6400 at Gear 1 you are probably better off. Just something you have to test.

I would not mess with the reference clock unless you want to go for extreme tuning.

36 x 100Mhz = 3600Mhz or 7200 MT/s (101 would get you 7272, 102 would get you 7344) Stability might go out the window though, and you are already there.

 

[ediofs]

I'll see how it goes, first I'm just going to go down in frequency, 7000 MHz test is running now.

As for reference clock, I can only set it to 100 and 133 MHz. The bios gives me presets for the memory frequencies which set frequency, reference and gear all at the same time.

 

[Eximo]

I suppose 133 might let you run gear 1 at higher frequencies? Haven't run into that one yet. Somewhere the CPU base clock will be involved, so that might have some weird effects.

 

[ediofs]

One more question: what's the best program to test DDR5 stability?

 

[Eximo]

memtest x86 is still the defacto standard.

 

[ediofs]

I ended up using Memtest86+ and TestMem 5. I'm now at 6400 MHz with the XMP timings (for 7200, so they're probably a bit looser than necessary). DRAM voltage/VDDQ both at 1.25V, 1.20 didn't work. I reduced CPU VDDQ and VDD2 to 1.25V as well from whatever it was set to after enabling XMP. Motherboard automatically set SA to 1.20V from the default 0.80V which had me a bit worried but it seems like 1.20 is still well within safe margins.

By the way, I also did a bit of googling on the gears, turns out DDR5 doesn't support gear 1, because IMCs don't really like going much over 2000MHz. So even at 4800MHz RAM, the IMC wouldn't be able to keep up.