Hi.
I have spent some time working on some OCs on my 9850X3D with 6000CL26 G.skill 48GB M-die kit and wanted to share an actual ingame performance comparison.
I ran Borderlands 4 at 4K DLSS balanced with an RTX 5090. I then let the system heat up for 5 minutes before starting an average measurement in MSI afterburner and HWinfo over 15 minutes in the same indoor and CPU heavy area to avoid variance.
Below you may find a link to screenshots of my 6000CL26 2200FCLK set-up vs. 6400CL28 2133FCLK.
Both run with PBO +75MHz and per core CO, where 1 less tick is required for stability in CO and 2 ticks lower on max frequency in curve shaper for 6400 compared to 6000.
As you may see during the benchmark the CPU runs roughly 0.5°C hotter and pulls 8 more watts with 6400MT/s. The IO die runs 2°C hotter and SOC power is also around 8 watts higher.
Effective clock speeds for 6000 are 85MHz higher than 6400, I assume due to more power available and the slightly better CO. Even so the 6400MT/s wins in avg. 1% and 0.1% lows by 1 fps. This is repeatable, but extremely insignificant.
So to people with 9850X3Ds, if you are just gaming, I would recommend 6000MT/s 2200FCLK over 6400, as the difference is negligible with higher voltage requirements (VSOC/VDDIO/VDDP/VDDQ/VDDG). The core boost offsets benefit of higher UCLK. The CPU will also last longer with lower voltages.
6000MT/s:
6400MT/s: