Your RAM is stuck at 2666 MHz.
Your RAM is stuck at 2666 MHz.
Hey, I see the issue. You're using a B450 motherboard with an AMD Ryzen 9 3900X and Corsair Vengeance Pro RAM. The problem seems to be related to outdated or incompatible components. The 2666 MHz speed you're getting is likely due to older RAM modules that don't support higher speeds. Also, the RTX 2070 Strix and your previous Corsair Vengeance sticks were affected by a recent update, which might have caused instability. Check if your RAM is still supported by your motherboard and consider upgrading to newer, higher-speed modules for better performance.
Explore various memory channels. Test single and dual options. Check for BIOS updates.
Take the 4000 kit and obtain a standard 3200C16 or 3600C18 package. Such high-end CPUs won’t reach 2000MHz clock speed, so post-shenanigans won’t help much. The 4000 is too slow to notice any benefit from desync FCLK adjustments. Yes, adjusting the FCLK should work, but it might lead to a setup that runs even slower than regular kits. Are you sure you want top RAM performance? Because otherwise, just get a generic 3200C16 or 3600C18 and add about 32GB—those are very affordable now (~50$ new). Performance is decent enough, just enable XMP and it should work fine. If you’re okay with that, consider getting four HMA41G6AFR8N or M378A1G43EB1 sticks for a quad 4x8 configuration and overclock to around 3800. It should be straightforward since those models have solid ICS capable of handling more than 4000. They’re older 4Gbps ICS, so they’ll keep the TRFC tight around 300 or less.