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Trying to stabilize Corsair Dominator 4000 with Ryzen 9 5900x

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Frizzle012

New Member
Joined
Feb 14, 2021
I am pretty new to overclocking so please excuse me for any ignorance, Im still trying to learn enough to be dangerous, but was hoping some folks could help me out here!

Specs:
Corsair Dominator Platinum RGB 2x16 4000MHz
Asus ROG Crosshair VIII Dark Hero
Ryzen 9 5900x

I can turn on XMP and the memory will run seemingly without issues, but I was hoping to try and get the fabric clock closer to in line with the memory clock which I know is important for AMD CPU's.

The XMP profile is running at:
mclk: 4000
fclk: 1800
uclk: 1000

19-23-23-45 @ 1.35V

I CANT get the system to POST when setting my memory clock to 4000 and FCLK to 2000, however the system does POST for all values up to 3933/1966. I figured since it does POST and run at a 1:1:1 I could start here and optimize for this speed?

First question is, is this a bad approach? Second, when running at 3933MHz the system is unusable, most applications take a long time to open and everything lags pretty bad. I was thinking that maybe I need to increase some voltages to stabilize the system at this frequency.

Reading here:https://www.tomshardware.com/reviews/amd-ryzen-9-5950x-5900x-zen-3-review/3 they got a similar configuration to run reliably by increasing the fabric voltages: "We had great results with memory overclocking with the Ryzen 9 5900X — we dialed in a 2000 MHz fabric and DDR4-4000 at a 1:1:1 fclk/uclk/mclk ratio, beating the best results we've reached with the previous-gen Matisse processors due to the general limit of a 1900 MHz fabric with the previous-gen chips. Just dial up the CCD and IOD voltage to 1.15V (not higher than 1.2V), and you should be good to go to increase the fabric clock to 2000 MHz."

Ive seem some folks say to increase the DRAM voltage as well to 1.40-1.45. I didnt want to make any of these tweaks yet until someone gave me a bit of a sanity check here on if that should be the next step or if I should rewind a bit.

I've attached my SPD too if its valuable.

spd.png

Thanks for any help!
 

Woomack

Benching Team Leader
Joined
Jan 2, 2005
99% of processors won't even boot at more than 3866/1933. Most won't be fully stable at 3866/1933. In most cases, there is no way to make it work at 4000/2000 using additional voltages or anything else. Another thing is that two 8GB memory modules usually run 1-2 ratios higher 1:1. 4x8GB or 2-4x16GB overclock worse but it's a matter of IF/IMC.
I recommend setting 3800/3866 and tighter timings like 14-16-16, 14-15-15, or 16-16-16 (a matter of voltages) ... or try to stabilize 3933. It will give better results than 4000 at more relaxed timings.
 
OP
F

Frizzle012

New Member
Joined
Feb 14, 2021
Thanks Woomack, I ended up getting 4000/2000 to boot, but had a few restarts and decided (like you said) its probably easier to just try and stabilize 3933. I thought I got things in a relatively stable place and successfully passed 6500% of ramtest and anta777 config on TM5. I know Id have more to do, but noticed I was getting pounded by WHEA warnings.

It looks like some forums and reddit have different opinions. Some seem to think its a BIOS issue and harmless while others say its voltages and WHEA are always a problem.

whea.png

I reset everything to default and started increasing MCLK and FCLK in sync and looking for WHEA warnings. From this, without changing anything else, I start seeing them as soon as I am above 3800/1900 which I think may be due to the fabric clock being above 1900.

I tried to adjust levels per DRAM calculator to see if things would stabilize, but was just getting the above WHEA warnings at idle without doing anything:

3866/1933 @ 16-21-22-21-44

DRAM 1.45
SOC 1.15
CCD 1.05
IOD 1.05
VDDP .95

Is there anything that seems to be wrong or im missing or should I just stop at 3800 and optimize from there to avoid this issue?
 

PolRoger

Member
Joined
Jul 31, 2005
Thanks Woomack, I ended up getting 4000/2000 to boot, but had a few restarts and decided (like you said) its probably easier to just try and stabilize 3933. I thought I got things in a relatively stable place and successfully passed 6500% of ramtest and anta777 config on TM5. I know Id have more to do, but noticed I was getting pounded by WHEA warnings.

It looks like some forums and reddit have different opinions. Some seem to think its a BIOS issue and harmless while others say its voltages and WHEA are always a problem.

I reset everything to default and started increasing MCLK and FCLK in sync and looking for WHEA warnings. From this, without changing anything else, I start seeing them as soon as I am above 3800/1900 which I think may be due to the fabric clock being above 1900.



I tried to adjust levels per DRAM calculator to see if things would stabilize, but was just getting the above WHEA warnings at idle without doing anything:

3866/1933 @ 16-21-22-21-44

DRAM 1.45
SOC 1.15
CCD 1.05
IOD 1.05
VDDP .95

Is there anything that seems to be wrong or im missing or should I just stop at 3800 and optimize from there to avoid this issue?

I have this same WHEA 19 issue with my 3950X.... But my sample exhibits the issue starting with UCLK speeds @1866Mhz or 1900Mhz.

I can boot/run my chip at 3733MHz/3800MHz 1:1 but it will generate lots of WHEA 19 errors in Windows. I don't like the idea of corrupting my Windows install so I'm now running with memory speed @3600MHz/3666MHz. (Unless I'm specifically trying to test my setup for a possible solution/remedy.)

At this time I'm not sure if there is anything that can be done about this issue??

You can read my posts in this thread here:

https://www.overclockers.com/forums...ssion-Thread?p=8160504&viewfull=1#post8160504
 

Woomack

Benching Team Leader
Joined
Jan 2, 2005
I'm not digging into various errors. Typically when I see that the PC is 100% stable and crashes quickly at a +1 IF ratio then I assume that the CPU can't handle it. The same was with every Ryzen generation and somehow I wasn't investigating that as nothing helps in that.

Ryzens act like 100% stable till some point, next ratio is bootable and benchable but is already generating errors and the next +1 is not booting at all. You can try to stabilize that bootable/benchable ratio with voltages but in most cases, it won't work.

This is also a reason why I like to play with 1:2 ratios and high memory clocks. As long as you have a good memory kit and above-average IMC then it's easy to stabilize and performance can be as good as at maxed-out 1:1. Not every software likes 1:2 but usually can at least match something like 3600 1:1 and tighter timings while other tests/games can pass the performance of 3800 1:1. This is also why some extreme overclocking profiles are something like 1:2, 4133-4400, and tight timings like CL13/14. I typically set 4800+ CL16/18, depends on IC.