I recently purchased 2x32GB DDR5 RAM designed for 6400MT/s to use with my Ryzen 7 9800x3D processor. Unfortunately, even with Expo enabled, the RAM isn't stable and crashes when I play Cyberpunk. After switching Expo off, it now runs at 5600MT/s, allowing Cyberpunk to run smoothly. Is there a way to achieve stable performance at 6400MT/s, or have I wasted my money since the official AMD site states the Ryzen 7 9800x3D only supports up to 5600MT/s? Thanks for any help!
6 Answers
First things first, make sure your motherboard's BIOS is updated to the latest version. That can play a big role in improving RAM compatibility with Expo/XMP. If that doesn't help, you can try tuning it yourself. If you're okay with running below 6400MT/s (like 6200MT/s), try enabling Expo for those timings and then lower the frequency without changing the timings—it could stabilize your setup!
Keep an eye on your UCLK running at 3200MHz as it needs to be 1:1 with the memory clock (MCLK), which only the best CPUs can handle. Try setting the UCLK:MCLK ratio to 2:1 and then enable XMP. Even if it won't perform perfectly, if that works, you'll know that's your issue. You might be fine running at 6000MT/s otherwise!
I recommend watching some tutorials on hardcore overclocking—there's a good channel on YouTube dedicated to setups just like yours. They might have some tips that could work for your build!
It sounds like your CPU might be running at a default speed of 5600MHz since that's the standard for now. Anything above that is considered overclocking. For AM5, hitting 6000MHz CL30 is a sweet spot. You can definitely try that; sometimes higher speeds don’t work anyway. Just be careful with those overclock settings!
Zen 5 can sometimes exceed its rated speeds, but just a little. Its memory controller has limits, and anything over 6000MT/s can be tricky. You might have just had bad luck with your silicon. If you haven’t already, enable Expo and see how it handles at 6000MT/s CL30; at least you'll know you're not missing much performance if that works!
What motherboard and RAM do you have? If you can, include the exact models. It'll help us see if they check out against the QVL (Qualified Vendors List).
Totally agree, BIOS updates can make a huge difference! I've seen similar improvements before.