Re: [256.25 8600GT] Unusual (fan?) Sound
I wouldn't really call it a 'hiss', it sounds more like a 'sick fan' or a fan ticking.
glxgears (non-fullscreen) with vsync off does sound a little like a whine (quite quiet).
The sound is louder under a full screen opengl game (HoN), than the sound while (accelerated) scrolling in a web browser.
This is likely a bug in the updated driver. It could possibly be my cpu fan, but as stated, it's not present when backdating to the previous driver.