Strange stuttering when playing games

[flyer590]

I am having strange stuttering issues when playing games on my PC. Some games do it more than others, but especially newer games like Crysis will run fine then suddenly the framerate will drop to almost 0 FPS for 3-4 seconds. Here is a graph of FPS from a couple of minutes of playing Crysis to show you what I mean:

I thought the issues was related to my old 9600GT, but I have since upgraded to a Radeon 5770 and it is still doing it. I also installed Windows 7 RC1 over XP but this didn't help either, which leads me to believe it is a hardware issue.

One interesting thing to note is in 3DMark the graphics test run perfectly smooth, but the CPU test gets the stutters. I then ran Prime95 for 12 hours straight to stress test the CPU, and it seemed to do that fine (no crashes).

I have also run Memtest86 but get no errors, and scanned the hard drive for bad sectors but there were none. I would appreciate any help in getting this fixed, as I am completely stumped as to what could be causing it.

Here are my specs:

PSU: Enermax EG425P-VE (420W)
Motherboard: Asus M2N-MX SE
Video: Sapphire Radeon HD 5770 1GB
CPU: AMD Athlon64 X2 6000+
RAM: 2x 2GB DDR2 A-data
HDD : Seagate Barracuda 250GB 7200.9

 

[ch33zw1z]

What are CPU temps under load? What case and cooling setup do you use?

 

[flyer590]

Aha, that's it! I checked the case fans and they weren't plugged in (don't remember why). Got them going again and it seems to be fine playing games now.

I'll probably invest in a CPU cooler to replace the stock one too. Thanks for your help

 

[Craig234]

Nice. I was suspecting OS swap issues. I would have thought it likely for heat to cause worse symptoms.

 

[flyer590]

Yeah same. I checked the CPU temperatures before and it was around 60-65C which I didn't think was too hot. Glad I've figured out what was causing it.

 

[ch33zw1z]

Glad it was an easy fix, could've been much worse!