This past week I've been trying to tune the memories (4x64gb CUDIMM 6400MHz CL52 from kingston) on my 9950x+x670e pro art a bit further.
I had already managed to achieve 4800MHz 42-42-42 stable from previous testings, with VDDSOC=1.2V, and VDDIO=VDD=VDDQ=1.3V
No matter what, I could not get 5000 or 5200MHz to work properly whatsoever. I even tinkered with the terminations, mostly using random values that I saw from other setups, to no avail. Since I'm using the iGPU, it was clear when thing booted up and were not stable due to all the graphics artifacts going on, and tests such as y-cruncher and stressapptest failed really quick.
Only thing I managed to do was to manually set the FCLK to 2000MHz, and lower the VDDIO/VDD/VDDQ voltages to 1.25V instead of 1.3V.
At the current 4800MHz 42-42-42 settings I can manage ~50GB/s on intel mlc (65% of the theoretical 76.8GB/s bw that 4800MHz should achieve).
For comparison, my 5950x with 3200MHz manages 37~42.5GB/s on MLC (83% of the theoretical 51.2GB/s bw that 3200MHz should achieve).
Those numbers actually seem to be on par with the
results from chipsandcheese:
View attachment 398560
Instead of trying to push the memory frequencies further, I'll try to see if I can tune timings a bit more and hope that this improves the memory bandwidth.
So far trying out 4800MHz 28-39-39 made the system not even post, and I stopped at that since I got too lazy to clear the CMOS
I've also seen talks that a FCLK out of sync may reduce perf, I'll see if changing this improves memory bandwidth in any way.
