UT99 slowdown occuring

I know its old, but i threw Unreal tournament GOTY on my new laptop. Laptop is gateway p-6860fx. Definately has the power, but for some reason is having a slowdown of the game occur in open evironments. I don't think it's low frames, while playing bots, its like the matrix for a few seconds and then back to normal....repeats in another few seconds. Any ideas would be nice, cause i'm out. The game does play decent in a window, but i still see the slowdown.