Serious audio and frame stutter to crash

Hello. I recently started playing DD2 again after missing quite a few patches. The game always worked just fine for me until now. When I launch the game and start playing everything goes just fine. But after I've been in game playing for about 15-30 minutes or so I slowly start getting some light frame stuttering. If I stay in game for another 15-30 minutes after this starts to happen I start getting some serious audio skipping (music, sound effects, and even audio from other sources like ventrilo and media players) and huge frame skips. Eventually the game just crashes and all other sources of audio go back to normal. I have tried reducing the graphical settings, using/not using vsync, verifying the game cache (steam), uninstalling reinstalling, even deleted everything pertaining to DD2 in appdata and residual files left in steam apps and registry entries after the uninstall. I also tried modifying multiple this in the baseengine.ini. I can't seem to pinpoint what is causing this.

(also its not an overheating problem I monitored temps while playing max gpu and cpu temps never exceeded 60c)

(also does not happen on any other games)

I did find a video someone uploaded from DDE that shows the exact problem I am having with DD2. I did not record this video:

Any advice on how to solve this issue is welcome.

PC specs:

Win 7 ultimate 64-bit

i5-2500

Nvidia GeForce GTX 980

16GB ram