Low FPS even with good computer

[UtopiaX]

Hi so I just got the new dell XPS with the i7 processor and got melee all set up on dolphin. first time I ran it, it was running really fast at over 60 frames per second and the game was actually too fast running at like 120% speed. Then a day latter I tried it again and it was running at 60 fps even which was awesome. But now a week later trying to run it and its running at 30 fps and 40% game speed which makes literally no sense to me.  Any help is greatly appreciated as all the standard speed up options don't that I tried so far haven't really helped. Thx!