I just got GTA V for PC and it was running 70-90 FPS on Ultra (without MSAA on). But after I play for more than a minute or two, the framefrate will drop to 40's and well into the 30's. This is while testing the game in the same area. The framerate will increase for about 15 seconds after tabbing out and in again as well, then drop down into the 40's again. GPU/CPU usage rarely rise above 70% in both high and low framerate scenarios. Running a GTX 770 4GB and an AMD 8350 8 core 4.0 GHz with 16GB of RAM