It requires a 350Mhz minimum,
So I wouldn't recommend it, I've played BG2 on the minimum SR, and the load times took forever, I think it will be the same for IWD2
Most games lately have hardware detection on Installation program or when you run the game at the first time. The program should refuse to run when the hardware spece doesnot meet min req.
It's best not to try anything under minimum requirement. Beside it's a waste of time, the game developer also have try minimum requirement and see the result
If you like this game so much, buy a new computer. But if you don't want or can't buy a new computer, you can ask a friend with a better computer to let you play on his machine. This game is great, so you can't miss it...