Just checked, the game only uses 600MB VRAM, which isn't very much. I guess you are right, it probably isn't a streaming issue.
BTW, I am running the game in "Fake Fullscreen" mode. Try it, maybe it will solve your problems.
I've fiddled around with all the possible combinations of display settings. That actually makes it worse for me, shedding 5-6 fps instead of increasing them. Other than lowering resolution to 1280x720 for frames, I don't know as 1600x900 isn't on the list for me if I want to get frames. Unfortunately 1280x720 looks like crap on a 1920x1080 screen lol. Playing it windowed makes it too small/frames are back to what they were at 1920x1080 so it wouldn't make sense for me to do so.
