IMO, power can cause odd issues like that as I'm experiencing the same thing myself. But for me it's just my single gaming PC that I have at home. My mouse response feels completely different whether my ceiling fan is on or off and when it's on I can feel a difference in mouse response depending on the speed of the fan (low, medium, or high). Unplugging my Philips Hue lightstrips and lighting helps with the feel a bit as well.
I am actually going to be able to rule out power as the culprit as I have a double-conversion UPS coming in tomorrow. Basically that will isolate my system completely from any "power issues" that I may be having. If it doesn't end up fixing the problem, then I can confirm whether or not it was even a power issue in the first place.
My aim also feels different depending on what I have my PC + monitor plugged into. Direct into the wall, into a surge protector, into a cheap Furman power conditioner, etc... they all result in different feelings in my mouse response. That is why I have kind of narrowed my issue down to power but we'll see tomorrow.
As for your issues at a LAN... who really knows until you can narrow it down. There are so many things that can effect mouse aim. Nvidia settings could be different from computer to computer (if they even have Nvidia video cards that is), background tasks, FPS differences? So much more.
Last edited by gunit2004; 06-24-2019 at 03:29 PM.