For me this game currently runs best with EFB->RAM and hashless branch from one of the last posts here:
http://code.google.com/p/dolphin-emu/source/detail?r=b7f4d59c6dc2d67d80da3b92ad07b394d7729fc9&name=Hashless
http://code.google.com/p/dolphin-emu/source/detail?r=b7f4d59c6dc2d67d80da3b92ad07b394d7729fc9&name=Hashless