Funny you should ask I just recently discovered how to fix that problem. All you have to is to set EFB copies to RAM or turn your texture cache to safe(changing the texture cache doesn't really much but if you don't fix you EFB copies the heat effect will cause that weird image splicing thing). Your display will still do that weird waving thing but at least you should be able to see what you're doing.
Back to the FPS problem, I changed the resolution back to .75 and it definitely helped. Thanks
Although I think the other guy is right in saying that my game will always be slow. Ah well at least it has become a bareable speed(10 FPS lol )
EDIT: Oh! lowering the resolution actually fixes the heat wave problem. I lowered my resolution to 1x Native(640x520) and when I went into the volcano the heat problem was SO much better. You can barely see the waves anymore and it improved my performance(The only problem is lowering the resolution makes the game graphics crappier). But you don't have to play all the game with that resolution just dragon roost cavern.