Emulator Problem: SMS in Dolphin dont run in my PC?

My problem:

I have a pc with the following specifications:

Core 2 Duo 1.8ghz
EVGA Geforce 8400 gs ( no oc )
Win XP
1GB RAM

I have played MW 2, MW 3, BO, MOH 2010... on full, but 800x600.

But when I decide to play Super Mario Sunshine on dolphin emulator, I run this perfect the first mission (20fps), but after that on the main island, I run at 10-15 fps, very bad : (

I adjusted a few things but nothing, any tips or ideas?

This is exactly how its preforms for everyone. Look forward to 4.0 should be any day now. If you want to make your computer better so it can play SMS then you need a sandy bridge $$$. Though the Dolphin team has made a lot of improvements in speed so wait for 4.0 first.

4.0 is coming out? can't wait! ^.^

i can almost get the games at playable speed hopefully 4.0 fixes these issues.

has anyone seen the compatibility list on wiki ?
it's in serious need of updating and revising ,as some of the listed games don't work

dolphin 4.0 ey well theirs about 150 revisions to go yet (latest is 3.0-850)

i'm planing on getting a sandy bridge ,i'm just hoping that it won't make my emulators work worse ,but knowing my luck