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Help! G .skill 48GB 8000 stable parameters

Level 9

CPU i9-13900Kf (SP 96)
RAM G .skill 48GB 8000
XMP1 and XMP2 are less stable
For example: Battlefield 2024 and Cyberpunk 2077 will all crash~
I am not a person who is good at BIOS field and testing stability with software.
I hope you can help provide a rough setting direction so that I can use the 8000 frequency stably.


Accepted Solutions

That's an open-ended question and not one that's easily digestible if needing to ask. Voltage alignment where adjustment is needed for overclocking can take time and a methodical approach, as well as a reasonable understanding of what the voltages do.

"How low" isn't anything anyone else can tell you. Given the MC SP score is fairly low, consider lowing the DRAM Frequency to 7800. If still unstable lower until you're able to achieve stability.

I did cover 8000MT last year in this article, but obviously, your mileage will vary.

13900KS / 8000 CAS36 / ROG APEX Z790 / ROG TUF RTX 4090

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Super Moderator

Hi @darkiria 

Is the system stable at Optimised Defaults?


You can try the DIMM Flex profiles under AI Tweaker > DIMM Flex > DIMM Flex Profiles. Select the 2x24GB m-die profile and then manually set DRAM Frequency under AI Tweaker to 8000MT.

See if this yields better results. It's a more aggressive profile, but it elevates some of the associated voltages which may aid your CPU sample.

13900KS / 8000 CAS36 / ROG APEX Z790 / ROG TUF RTX 4090


Unfortunately ~ the old version of APEX does not seem to support DIMM FLEX
And the 8,000 set seems to be no longer among them~~
Is there any other way to adjust it?

Apologies, I didn't spot which board you were on.

Try the following:

1. Clear CMOS

2. Set XMP II

3.AI Tweaker > VDD & VDDQ between 1.4 and 1.45v

4. AI Tweaker > Advanced Memory Voltages > Set MCVDD 1.45

If above doesn't aid stability:

AI Tweaker > DRAM Timing Configuration > Maximus Tweak Modes > Tweak Mode 2



13900KS / 8000 CAS36 / ROG APEX Z790 / ROG TUF RTX 4090

Thank you for your reply~ It is still not stable according to the above settings~ I simply test whether cyberpunk 2077 crashes when executing and make a simple judgment~ The optimized default is no problem~ But the current frequency of 8000 will continue to crash~ Still Is there any solution?
I even looked up a lot of related discussions on voltage adjustment~I never got a good improvement~~It's very painful...

Hi @darkiria 
Go to Extreme Tweaker > AI Features and run the MC SP test. The system will then reboot and conduct a short test. Once complete, renter the UEFI and navigate back to the AI Features menu. Report back here with the score given.

13900KS / 8000 CAS36 / ROG APEX Z790 / ROG TUF RTX 4090

renter the UEFI I don't understand this~Sorry


He wanted you to run the MC SP  (Memory Controller Silicone Predictor) test.. which would give us an idea of the quality of the memory controller on your CPU. 


Z790 Apex Encore, 14900KS, Corsair 7000D, Crucial T705 2TB, Corsair Titanium DDR5 48GB 8200, Asus RTX 4090 OC STRIX, MSI MEG 1300w PSU, Corsair ICUE LINK 420mm 14 QX Fans, Acer Predator X38 S 177hz | Z790 Apex Encore, 14900KS, Corsair Titanium DDR5 48GB 8200, Crucial T700 2TB, Corsair HX1000 PSU, Corsair 5000D, Corsair ICUE LINK 360mm, Asus RTX 4090 TUF, Alienware 38" Curved 144hz

Currently set to XMP1 full default
Lower the frequency from 8000 to 7000 and everything is stable
The game does not crash~~The AIDA64 baking machine does not report any errors~~
Am I unable to stabilize at 8000 frequency due to CPU IMC constitution?