game play pausing

[rrcn]

I've noticed that while playing NFS Underground that the game play will stop and around 20 sec later, game play will resume from where it stopped. The game is not exited. Its as if you were to hit the pause button on a VCR. I am wondering why this happens? I am thinking that it may be a heat related issue...?? I tried running it with the sides off but no luck. If so, how can I keep my card cooler? Right now I have 2 80mm blowing in and another 80mm blowing out. Could it be a cd-rom issue?? I dont hear the cd rom reading when the above situation happens nor do I see the light turn on. I have the latest nVidia and VIA drivers.

**Nothing is overclocked**
AMD Athlon XP 2600+ 333FSB Barton
512MB DDR333
120gb maxtor
gf4 Ti4600


All information is greatly appreciated.

[Whitehawk]

how how is ur cpu running??? hold the 'Delete' key to get 2 ur bios at startup to find out the temp