Input lag, rubberbanding, floaty cursor

[Mercron]

Ive been lurking this forum for a while, I seem to have the exact same problems as a lot of people:

small mouse movements feel very hard, mouse feels heavy or floaty, inputs are delayed a random amount of time (inconsistency), online games rubberband a lot

I came here to ask about something very specific: I live in rural spain, 2 years ago (after lurking some in this forum) someone mentioned their ground being faulty. I tested the sockets on my room and they read 390 volts. Weird. So I called an electrician, he measured and confirmed 390 volts, and he opened all of them until he found one that had a loose ground cable. Then he fixed it and re-measured, this time it said 230v (good reading)

However, the lag didnt stop. So that got me thinking: what if there is something wrong with the electrical installation still?

So then, I ask: how on earth does a loose ground cable make the multimeter(both mine and the electrician's) read 390 V? Obviously the PC wasnt being fed with 390 volts, otherwise it would have been wrecked, but there might be something causing problems (such as EMI or whatever).

Any ideas of what could have caused that so that I can maybe ask better questions to an actual electrician?

To be clear, the question is this: what could have caused my room's circuit to read 390 volts?


Thanks in advance.

[MK92]

390V AC on your socket that goes to your PC would instantly destroy the PSU, not cause you input lag lol...so you both measured something wrong.