Well that's probably a Mantle issue in your case. There are memory leaks going on with that right now. But KD is running an Nvidia card so that shouldn't be the issue here.. Then again, that might just be another issue with the patch..
It's a good idea to make sure you tell Origin to specifically launch the 64bit exe for bf4 as well. It should do on auto if you have a 64bit os. But it's worth a shot anyway. Might help..