I have this weird issue with Dungeon Siege 2 where the game runs fine for the first 10 minutes or so and than it starts to stutter and the fps becomes irregular but never below 60 fps. Before that the fps remains stable. What's even weirder is if I close the game and start it again the problems persist but when I reboot my computer and start the game afterwards it runs fine again for the first 10 minutes.

Looked around for performance settings and tried running in window, compatibility mode, vsync off, used all kind of settings in the ini file but nothing worked.

Anyone a suggestion?

this happen to me too, but in my case its constant, I don't know what to do because I cant play the game like this, but I notice when I move the cursor the stutter start.

One solution I've heard is that vsync in the nvidia control panel can cause issues with dungeon siege 2. Turn off the vsync and see if that helps.