I'm observing the same behavior here.
I usually flick my mouse cursor over my (dark) taskbar (Made a habit out of it to remind myself there's some latency that I hate but could never pinpoint) because white and black is a slow pixel transition (G2G) and adds up to the total latency observed.
Disabling MSI mode on Intel XHCI controller made my cursor (and ingame) almost a 1:1 response.
This monitor's input to signal latency is also rated as <4ms and yet it felt way higher somehow, and I wasn't under the illusion that I could actually notice 4~ms if input to signal lag personally. But its pretty easy to move your mouse left to right, observe the cursor and see that both don't sync up. Definitely an improvement!
Strangely I don't think this is necessarily just an Intel issue as I observe the same latency with an Asmedia controller. (Never tried disabing MSI on that though)
Lots of placebo's around, but I'm pretty sure this might be some weird thing that prioritizes bandwidth over latency in regard to the usb controllers/win10 (Power saving and max bandwidth are basically the trend these days, and it usually always goes at the expense of latency.)
I'll admit I don't think most people will be able to tell, but for me my mouse response feels way more raw.
Maybe this is why I2C controller for Touchpad on my notebook is forced on emulated interrupt, they are already so damn laggy, MSI would make it worse ^^
Last edited by Marctraider; 07-27-2020 at 04:47 PM.