I tried posting a reply about my experiences with this issue last week and it was autodeleted. Maybe it's because there was a video upload linked?
Been having the same problem since early September. Not sure there's a fix out there, unfortunately; I've tried plenty of stuff.
This was after about an hour-long session, after which it had started having problems on 250Hz during matches. Notice how it's initially smooth at 250Hz and increasing polling rate progressively makes it worse, up until 4K is making it lose several seconds. After that, switching back to 250Hz is noticeably worse than at the beginning of the recording.
I don't think I have it quite as bad as OP, maybe because I'm starting with stronger hardware (i12700K/4090). Still, this shouldn't be happening at all; it's something that flipped overnight.
My observations are:
-The effect is worse as polling rate increases; 4KHz is completely unplayable but even lowering it further down still incurs drops.
-There appears to be some kind of buffer that accumulates. If I start a session at 4KHz, these frame drops start within seconds, whereas if I leave it at 250Hz, I can play for an hour or so. Closing and reopening the game resets it.
-Moving the mouse very slowly mitigates the impact of the problem, which makes sense - at 4K polling, the mouse needs to move a lot of physical distance quickly to saturate that polling.
-It's not a simple framerate drop - I forgot to record audio, but there's gameplay desync where in the worst cases, bullets don't register until seconds after they visibly shoot and the audio plays.
I'd speculate that this is something CPU-related, since that's usually what causes high mouse polling rates to cause problems, but I've thrown a lot of latency solutions at the wall and nothing's had any real effect (in no particular order)
-adjusting graphics settings
-DX12 beta version
-reinstalling drivers
-isolating all USB devices
-disabling USB power suspend
-replacing mouse/keyboard (Lamzu Atlantis/Steelseries Apex Pro with GPX Superlight/generic mechanical keyboard with no software)
-tweaking NVCP settings for high performance
-reinstalling Windows
-clean install of GeForce drivers/reverting to older versions
-running Apex/EAC as admin
-disabling hidden CPU power savings settings in Windows Power options
-disabling CPU power saving settings in BIOS
-disabling hyperthreading cores
-isolating Apex/USB hub to separate cores
-tuning system timer
-disabling W11 HAGS
Bump. Next week is coming up on three months of having my crosshair skip around at 250Hz polling and still needing to restart the game every couple of matches.
There's been a motherboard firmware update since my last post that did nothing.
