Severely reduced performance when selecting 1440p 165Hz vs. 144Hz since at least linux 6.4-rc5, as VRAM clock stays low under load
When I let the display run at 1440p 165Hz, my 3D performance (e.g. games on Steam with VKD3D-Proton) is severely reduced to something like 5-10% of regular performance level, even though 100% GPU usage and full clocks (>2.6GHz) are reported. GPU ASIC power consumption is very low then, e.g. ~30W. When I set the display to 144Hz instead, the performance is back to normal. There are no other tweaks like overclock, overridden power mask etc. active.
This is with
RX 6700 XT Asus Dual
Lenovo G27q-20 monitor (default EDID) connected via DisplayPort (165Hz work fine on Windows)
Linux 6.4-rc5
Arch Linux with latest XServer / Plasma Wayland (same behavior)
I tried going back to 6.4-rc4, but it has some freezing/crashing issue (Again, with 165Hz only. 144Hz are fine).
Dmesg log: dmesg.log
Edit: 165Hz work with Linux 6.3.6 without freezing/crashes, though (as expected) idle power consumption is very high due to VRAM not lowering clocks.