Could just be the GB one. Its being investigated
. What I can tell you is the loss is only noticeable is certain games when benchmarking plus 3dmark stuff.
I didn't notice at first until I compiled all the data for RTX 4090 benchmarks. Odd 4800 CL40 beats 6000 CL30 I said to myself... Wasted half the day checking other ram, changing BIOS settings to narrow it down. I realized I went to F22 to play with DDR5-8000. Back to F13C (10007) and everything lined up again.
Here is the rub. AIDA64 reports same latency and bandwidth. Loss on GPU stuff is margin of error for GPU bound. Cinebench and Blender is (lower), but unless you locked the frequency - impossible to tell.
3Dmark CPU scores that are affected by memory and of course games not CPU bound is the problem. So its somehow CPU and memory related, but subtle. 3Dmark was the only easy one to catch if you aren't actually looking.
I don't know if anyone will notice unless you have a massive set of data already like me.