Hello folks!
I just built a second (low budget) PC as a media centre with the following specs:

ASUS A7N8X mobo
AMD 2400 @ 2Ghz
9800Pro Graphics
onboard nForce sound
1GB (2x512) PC2700 RAM
160GB HDD SATA (video/music files)
40GB HDD IDE (OS and programs)
All packaged in a nifty full-size ATX media centre case.

The system is great for playing films, browsing the web and other mundane things but when I play a game which requires any effort by the graphics card it occasionally stutters (1 second pauses every 30 seconds or so). We're not talking Crysis or anything of that sort... I'm talking Halo, PGA2005, Lego Star Wars (all fairly dated stuff).

I've tried a multitude of drivers (I current have some older Omega drivers installed as they appear best so far). I've obviously defragged and cleaned up the registry. Any ideas?

Could a background process to causing the issue? (I'm not too hot with these)
Could it be an overheating issue?
Some forums I've read have mentioned sound conflicts... (again, what's all that about?)

I you need any further details/specs, let me know guys and gals.

Help me PCApex. You're my only hope!
Duplo

press ctrl+alt+del

click the "performance" tab

keep an eye on your cpu usage history meter, and see if there is any sort of spike in cpu use every 30 seconds or so, this will likely isolate the issue a bit further

What kind of monitor and resolutions are you playing at? Are you overclocking at all?
What OS? What kind of framerate are you getting in these games?

Stutters could be swap file access, you're OS disc is a little on the small/dated side. Set swap size to no larger than actual memory size. A background process or start up program could also be the culprit.

There's been no real changes in 9800 drivers in a long time, it's probably not drivers.

Thanks Antim... You hit the nail on the head... Smooth running all the way.
I love you guys!