We haven't had much chance to test the gameplay with Windows 10, which might mean there are some compatibility issues with it. Does this always happen, or is it specific to large maps (like the White House), and occurs when you're deep in the game with e.g. many NPCs already locked into rooms?

The alarm did go off so there would be more guards/cops than usual, I was about 15mins in and there was a bit of gunfire and more textures from blood effects but still its only a few sprites and lighting effects nothing too large... I hope.

Ok, thanks for the details. We're aware of some issues leading to frame rate drops, but don't have a ready fix at hand. We'll keep collecting info on these and hopefully find a solution in the future. Please let us know if you figure out something more, relevant to the case.