I really don't Know, DICE should be honest and tell us whats going on. I just bought BF4 and after running the Graphics test it said the quality of my system was bad and set everything to either low or off, and it still runs like crap. now apart from the fact that Iam running a 32 bit system, I have a i7 4770, a Sniper 5m M/B, 2 GTX 670s and the latest Nvidia Drivers. Surely dispite the fact of the 32bit, it should run better than it does. The stutter that I experience is the same symptom the I have only recently come accross on BF3. I suspect DICE have done something with the netcode. I sure hope they do something to fix this problem because BF3 is the best game out at the moment, and BF4 looks like it's going to surpass it once these problems are solved.
