I have a Q9400 quadcore processor clocked at 3.6 ghz, 4 gb ram, and an ATI 5850. Wind Waker runs at an almost perfect 30 fps. Every now and then I will hit a scene that drops to 20 but that was like right on top of a bed of lava for 10 seconds. The games I listed a couple posts up run at a perfect 30 or 60 fps (to run at 100% speed) and have few to no graphical inconsistencies.
I have been a lot of PMs about how to work this magic, so here are the links I used to get started:
This link will get you the latest builds:
http://dolphin-emulator.com/download.html
This link will explain the settings that tend to work best (that I use):
http://forums.dolphin-emu.com/thread-3533-page-1.html
This thread has a list of games and people trying to figure out how to get the best performance:
http://forums.dolphin-emu.com/thread-6003.html