Fast computer, slow gameplay ?

[lajkapeetes]

Hi,

I just downloaded Dolphin 2.0 and a New Super Mario Bros for Wii rom. I used these settings: http://www.youtube.com/watch?v=RzFG5dDsGX0

However, when I start playing, the speed is only about 60%.
These are my computer specifications:

Intel Core 2 Duo, P8600, 2.40Ghz
4GB RAM
32-bit operating system
Windows Vista Home Premium, Service Pack 1

I disabled all the unnecessary services, but I still can't seem to get this game playable...

What should I do?