GTA ViceCity Video hiccups

[Segageo64]

I'm using a P4 2.4 G with a ATI 9500 Pro video card and Windows XP Pro (Nothings overclocked!). I'm using the latestest driver for my video card dated 5-15-03 and I also tried updating the game to version 1.1 but nothing seems to help even when I tweak the games video display settings.
The game runs fine except for the slight hiccup or slowdown while moving every 3 or 4 seconds. Maybe this is normal but to me its kinda irritating. Does anyone else have this problem with GTA Vicecity or know what to do to fix the problem?