Perfomance spikes when playing games

Hi

Recently I experience random fps spikes when I'm playing games ONLY. The spikes doesn't occur during normal usage of the computer. I know these spikes are not the effects of playing new games on older machines

My specs are here--------------------------------------------------------------------------->

And I usually play new games rather SMOOTHLY. Even on medium settings.


This only happenned recently and still persists.

When the spikes occur these programs are running: the game being played, AVG antivirus, Spyware Doctor, Daemon Tools and occasionally utorrent.

I've checked on task manager when these spikes occur and there seem to be no other programs that is contributing to the spike (other than the game itself of course).
Haven't touched anything in my tower yet, only recently when I replaced a faulty LAN cable and a PCI LAN cuz my onboard LAN is fried.

I half suspect its my 1 and a half year old graphics card and/or ram. Also I suspect a virus though I reformatted twice but the problem still persists.

I'm now running Hijackthis in safe mode to check; can I post the logfile for those of you who are more knowledgeable?

My Specs:
Processor
Intel Pentium 4 HT 3.06GHz
Mainboard
GA-8IPE1000Pro2 (Gigabyte)
Graphics Card
ATi Radeon 9600PRO 256MB DDR
Memory
Corsair CL2.5 1gb (256x4) DCh
Display
Samsung SyncMaster 713N
Storage
120gb 7200rpm Seagate HD
Optical Storage
LG DVD Multi-Recorder (Black)
Casing
PERX Red Standard
PSU
400W Perx
Audio
Realtek AC97 onboard
OS
Windows XP Professional SP2

 

I'm still experiencing it, hence I'm asking for help. I'll provide other information related if possible.

I've updated my drivers but still having spikes, I've also reformatted my PC, defrag it but its still the same.

I've also upgraded my specs abit by adding a few things:-

Upgraded RAM to Kingston 2gb
GFX Card Nvidia GeForce 7600GS

 

What games are you trying to play? and by performance "spikes", do u mean that the performance will get really good for a second or that it drops?

 

I play Gears Of War and Call of Duty4, and I met both requirements to play these games. But at about 1-2 minutes of playing, the fps starts to drop and suddenly its normal again and I can play smoothly. It keeps doing that to every game I play.

Hence, the performance spikes I meant was that it suddenly goes to 100 for sometime and drops back down to like 70 or something.