I've had my rig for almost a year now and my video card has always hummed and squealed. It didn't make these sounds too loudly, I just thought it was normal. However, recently, when playing some 3D apps like Far Cry 2 and Crysis, it will sometimes completely freeze and the audio will slow down and then completely cut. The only way to exit is a hard reboot.
Here is my setup:
CPU: Intel Core 2 Quad Q9550 2.83 GHz
VIDEO: Nvidia GTX 280
RAM: 2 sticks of DDR2 2GB 1066 MHz
HDD: 500 GB HDD, nothing special
OPTICAL DRIVE: Super-multi drive
USB: One wireless dongle that is always plugged in