Well, I have a windows 7 x64 too, and a CPU @ 3'5, so it shouldn't be any important perfomance differency between your computer and mine, and I can assure you that I'm getting higher FPS on the x64 version that in the x86 version, the difference is about 10 - 15 FPS more o less.
If you are getting lower framerate try to use the JITIL version, and add this line to Dolphin.ini, in the [Core] section:
ProfiledReJIT = True
It will increase your FPS, but you must use rev 3820 or higher.
Ah, and don't forget to check if you are in dual core mode xD
If you are getting lower framerate try to use the JITIL version, and add this line to Dolphin.ini, in the [Core] section:
ProfiledReJIT = True
It will increase your FPS, but you must use rev 3820 or higher.
Ah, and don't forget to check if you are in dual core mode xD

