Baldur's Gate Dark Alliance for Gamecube question

[tx3000]

I am curious if the Game Cube version of Baldur's Gate Dark Alliance can be run without any slow downs?

I am using the Dolphin 2.0 This is my system
OS: VISTA Home Premium (32 Bit)
CPU: i7 @ 2.8 Ghz 8MB Cache
RAM: 4GB GDDR
GPU: GTX 260

And even on my system and specs it runs fine until it gets into an open area and or there is a lot of enemies on the screen, then it slows down quite a bit. Is there just no fix and something I am going to have to just deal with, or are there specific settings that this game needs to have in order to run fine.

Thanks in advance!