no such thing exists. pal has a default frame rate of 50 fps and ntsc has 60 (afaik). the games run smoothly from that point. if u really want a higher frame rate, turn off the limiter.
The problem with disabling the limiter is that you will get no boost in speed unless you reach 50/60 fps anyway.
You could try reducing the resolution and adjusting the counter factor to a higher value, but to actually hack the rom itself- that may be possible, but I wouldn't do that...