It's been bothering me for months now, but I've noticed in Ubuntu (or any distro of Linux I've tried), any major I/O activity will cause hitching and general slowness.

For example, if I try doing a file transfer from my network computer to the computer I'm using and try moving the mouse after a while, it might not respond for a second or so. Similar incidents occur in other cases too (right-clicking to get a context menu takes a few seconds, hitting the drop-down application bar takes a while, etc).

My HDD isn't top-notch (a WD Blue 500GB 7200RPM drive) but I don't recall it being nearly this bad in Windows 7, 8, or 8.1.

CPU activity during file transfers is relatively low (less than 10-20% on all cores of a Phenom II X4 @ 3.3Ghz). I'm using Gnome System Monitor (on Xubuntu) and can't seem to see what kind of HDD activity is occurring though. I have 8GB of RAM too, which is moderately being used (2.5GB), but shouldn't be a problem either.

Any ideas what's up? I've tried kernels between 3.8 and 3.11 (i'm using saucy currently with 3.11).