I recently upgraded my machine and installed Windows 7. Since then, I've been having a weird issue with the sound stuttering when in gunfights, eventually leading to the system completely freezing and needing to be restarted. It seems to "skip" every other gunshot sound or so, until the freeze. I captured the issue happening in fraps and put it on youtube:

http://www.youtube.com/watch?v=jBm_DnHNcz4

The issue only seems to happen when I'm in gunfights. Dialogue and other ambient sound effects seem to be fine.

I have the latest drivers for my video card and sound card, both of which are the same cards as in my last machine which ran Fallout 3 just fine. Here's my specs:

Fallout 3 (not New Vegas)
Windows 7 Enterprise 64
AMD Phenom II X6
8gb RAM
NVidia GeForce GTX 470
HTO Striker 7.1 sound card

Anyone have any ideas?

You have a CPU with more then 2 threads, try limiting the game to only use two threads for the game.

Open up the .ini file located in My Documents>My Games>Fallout 3. *Do not alter the one in the actual game directory labeled Fallout_Default_ini*
In the FALLOUT.ini find the line

bUseThreadedAI=0
change the 0 to a 1

then below it add the line

iNumHWThreads=2

I tried what you said but there was no change. Thanks for the suggestion, though.

Anyone have any other suggestions?