What causes small delays in computers/windows?

tornreality

Honorable
Feb 11, 2013
53
0
10,630
Hey guys, just a simple question or so I hope.. What causes small delays in programs even when there is no pressure on the hardware, well, at least that I can detect with the system monitor, let's say you are moving a browser window with a youtube video playing, and you notice jitter or even skipping while moving it across the screen especially when moving it quickly, what causes this, as far as I can tell there is not any pressure on the system itself, I have an i7, ssd, and 12 gb of ram on my main pc, it also happens on every single computer I have, so I think it most likely happens on everyone's systems you just have to be paying attention to notice it.

If some computer geeks can answer this that would be awesome!

TL:DR what causes programs lagginess when your hardware is more than capable to run it?