Random FPS loss

[Lude]

Im having a problem when i play CoD4. For some reason every couple minutes or so my FPS will drop to 30-35
(average 75-125). Ive check all my temp when running the game. I did the lagometer and and the line on top will have a thin yellow spike. The bottom one will miss a small scetion on line. What does this mean? Any help would be appreciated. Below is my system config.

screenshot~
http://xtremeassault.com/images/lagmeter.JPG


Thanks Lude.

CPU: AMD 6000x2
MoBO: Asus M2N-e Deluxe
Videocard: BFG Tech 8800gts 640mb
PSU: 550 watt Rosewill <-----This is the only thing i can think off, maybe need bigger psu??
RAM: 2 gigs of G.Skill (2x1024)

[The_Humungus]

I have an Nvidia 7950gt 512 mb card, and several times a game, especially during airstrikes and helo attacks, my fps drops from 91 down to low teens (once as low as 7) then goes back up to 91. I have aliasing turned off, and my screen res is set to 800 x 600 (Optimal setting).

My pc is:

Intel® 975X (Big-Arm) -
Core 2 Duo E6400 2.13 GHz, 1066 MHz FSB, 2 MB cache, non-HT, Conroe LGA775, EM64T, XD, EIST, VT
700 watt power supply
2 gig of ram

I have ordered a new 8800gt 512OC card, and will see if it changes. But could this problem be caused by something other than the card? Vista? Game? Any other reason???

Thanks.

[Lude]

Well i did some checking and my CPU usage in task manager goes way up. There is a process called "system" when im not in the game its at 0-1, In game it goes to 25-40. Others in my clan said theirs stayed at 0-3. Im thinking this is my problem. Anyone else have this problem? or now wtf this thing is.

~screenshot

http://xtremeassault.com/images/task.JPG