Emulator Problem: Kega Fusion 3.64 runs at 30fps in fullscreen

I have tried numerous things with settings in the ini and I seem to be stuck.
It was working a while ago but now I am at standstill.
I am at full 60 in windowed but switching to fullscreen gives me only 30fps.
Any help would be greatly appreciated since this is making me go insane.

Windows 8
Intel I5 3570K
GTX 770

I have the same problem. I run Windows 8.1 with a 745M Nvidia graphics card i7 processor. I can confirm only that fixes that used to word no longer do.