cpu usage

Hi,
i just wanted to ask whether its usual that when starting R4, the cpu usage goes up to 100%. I'm using the actual version of R4, got the latest drivers for my radeon 9800pro card and i think 2 ghz and 768 mb ddr should be enough.
By the way, the performance of R4 is fine, about 60 fps, using a resolution of 1024x768.
After reading some board topics, i already deactivated my antivirus program, but the cpu is still on 100%. So it takes e.g. a very long time to open the firefox browser, the taskbar and simple stuff like that and this is what makes me a bit "unhappy".
So please tell me if i can do something to fix that prob or whether that is -maybe- just "normal"
thanks a lot for answering
PS: I'm using two monitors: the first shows windows, winamp etc, the second one shows fullscreen R4
i just wanted to ask whether its usual that when starting R4, the cpu usage goes up to 100%. I'm using the actual version of R4, got the latest drivers for my radeon 9800pro card and i think 2 ghz and 768 mb ddr should be enough.

By the way, the performance of R4 is fine, about 60 fps, using a resolution of 1024x768.
After reading some board topics, i already deactivated my antivirus program, but the cpu is still on 100%. So it takes e.g. a very long time to open the firefox browser, the taskbar and simple stuff like that and this is what makes me a bit "unhappy".
So please tell me if i can do something to fix that prob or whether that is -maybe- just "normal"
thanks a lot for answering

PS: I'm using two monitors: the first shows windows, winamp etc, the second one shows fullscreen R4