I discovered this fix when trying to sort out my keyboard and mouse inputs issue.
Problem:
The opening splash scenes and cutscenes were jittery and had intermittent sound - the sound cut off for a second, or so, every couple of seconds. Also, in-game, the animations and transitions (e.g. between concourse and players cabin) were jittery.
Solution (for me, at least):
Run alliance.exe as administrator.
To do that:
- Navigate to your XWA folder
- Right mouse click on alliance.exe
- Chose Properties from the menu
- Select the Compatibility tab
- Make sure the tickbox/checkbox next to Run this program as an administrator is ticked/checked