I also have the problem of the sound cutting out - seemingly at random, but usually in ~5 minute intervals. Go the the menu and toggle the sound setting and it works. This is unacceptable...I didn't buy a Creative Audigy2 Platinum and relatively powerful 5.1 Logitec z-5400 speakers to use NOT use them.
I'm going to try switching my sound card to another PCI slot since I think I have too much IRQ sharing... I hope this works, but I doubt it will. I'll let everyone know if it does.
My specs aren't that great, but the game runs well considering my CPU and video card are getting somewhat outdated. Here's my build:
Nvidia2 motherboard (EPOX 8rda3+)
AMD 1600+ CPU (not OCd)
Nvidia Ti4200 graphics
The above mentioned sound set up
1GB RAM (512 x 2 dual channel mode)
The RAM is probably making up for a slow processor, but if the bulk of the sound is handled by the CPU as many have mentioned, then I'm probably screwed regarding the sound issue...fortunately a 2500+ Barton is <$100.