Will also post this here as it will also apply to 6800 XT users.
Did some memory performance testing in Red Dead Redemption 2 and again i saw the behaviour play out as i mentioned before, 2112Mhz appears to be the sweet spot, at least in games.
Testing was done using the built in game benchmark.
2160P
RDR2 DX12
Ultra Settings - Tree Tess Off, MSAA/Reflection Off Water quality High, Refraction/Reflection 3/4.
TAA enabled and sharpness 100%
5950X PBO
6900 XT 2270-2370Mhz Undervolted to 1.000v (actual in game core clock is minimum of 2300Mhz, peaks up to 2325Mhz)
21.2.2
Fast Timings On
No MPT, using default board power limit 289W+15% power limit so no chance of power limit affecting results as power draw was 220W-240W ish according to HWINFO64.
2012Mhz Memory Clock
2112Mhz Memory Clock
2150Mhz Memory Clock
This behaviour in memory clock performance has been the same now on 1x6800 XT MBA, 1x6900 XT MBA, and 2x 6900 XT Mercs.
Don't run your memory at 2150Mhz when gaming folks, you are possibly getting stock levels of performance. In synthetics you can crank it up to 2150Mhz and see gains, but games seem to see reduced performance back to near stock levels.