Ok, so since last driver update (2 days ago), the sound has been consistenstly crispy clear, and no weird graphics fuckups. I'm thinking the sound problem seems cleared, still waiting a little to see for the graphics.
Update: I've figured out the sound issue. Seems it WASN'T the driver (although it may have helped), but uTorrent! I was watching a movie, and suddenly I noticed scrathing and distortion again. Puzzled, I asked myself what I just did. I had just started uTorrent, so I shut it down. No sound issue. Open it back up, and hello scratching! Shut it down again and the issue instantly dissappears.. This also explains why it'd be fixed by a reboot, as that would shut uTorrent down. Who would have known? Thanks for the help though! It's always nice to have updated drivers.
No new graphics issues.