when I'm in a car & driving around, the game kinda jerks, or freezes for  couple of micro-seconds. the game play isnt smooth. 
whats more anoying, is if I've got the radio on, all the songs are also interuped by this.  
What can I do, I system is as follows: 
P4 3.0ghz 
512DDR ram 
256mb Ati Radeon 9550  
80gig sata 
asrock MB board with on-board sound 
please help