Batman Begins Frame Rate Issue

[appollo147]

I am having a real problem playing Batman Begins. The game will run at normal speed then, usually before enemies appear on screen it starts paying back really fast until all the enemies are dead then it returns to normal speed again. I have tried playing it on Dolphin 5.0-8715 64-bit, and Ishiiruka v1031(314869d85) 64-bit with the same results each time. Any help with this issue would be greatly appreciated.