Well, it may not be true anymore, but for a while r6515 was largely agreed upon to be the overall fastest revision of Dolphin, regardless of functionality and compatibility. Since I just needed all the performance possible to run it, I wasn't worried about anything else.
Not really. It's a nice middle ground between performance and compatibility but I think for most games older builders like r6000 are faster. And REALLY old builds are even faster. r4000 can probably run WW at fullspeed on a low end athlon X2 fairly easily.
i know this is an old thread, but would it be possible to get 144 fps?
There may be a way to do something through Nvidia's Control Panel. As I understand, they just made an option to limit the maximum frame rate, though I have no idea if this plays nice with Dolphin at all. Due to our rules about necroposting, we recommend you make a new thread about the subject to get more detailed answers.