I'm encountering this issue suddenly in a few rooms. It seems to happen in certain rooms but not with any particular characteristics I can pin down, and it does NOT occur consistently but maybe half the time. As pictured, the FPS drops considerably... then after a few seconds (sometimes 1, sometimes 4 or 5) it returns to normal. During this time, there is no change in swaps, in RAM, in the number of instances / particles / etc. I can't seem to relate it to anything that is happening in my game. It seems the workload does not change but either GM or my computer's ability to handle that work load somehow changes. Ideas? EDIT: It seems that this may be related to Anti-aliasing. When I use 8x AA, this happens as explained above. Lower settings seem to consistently prevent this problem from occurring at all. So wtf?