CPU spike issues! Help needed!?

Hi guys,

I am new to the site and have been digging around the net for the last few weeks to find a solution to my problem. Let me explain in more detail.

My system had a PSU blow-out about 4 months ago, it was a decent PSU so it saved all my other hardware from going down the toilet. Anyway, since then I got a new PSU, same wattage as my last one but a little better in quality. I put everything back together and reinstalled a new OS just for safe measure.

THE PROBLEM: When I watch movies, play music, games or view videos on YouTube I get these tiny spikes in my CPU usage that slow the system down for about 4 seconds. It distorts the audio/video/gaming feed and then catches up with its self again.

First I thought it was a bad version of flash, so I used an older version and the problem remained. I tried different browsers also just in case it was a software error, problem remains. I then thought that my HDD may have taken damage from ESD so I took that drive out and used a brand new one with another new OS, problem still there! I then put some new coolant and a new heat-sink on the CPU, that didn't work either. I checked my RAM to make sure that everything was running on the same frequency and it's all the same frequency. I also ran memtest86 and there was no problems with the RAM.

So I have kind of narrowed it down a little, weird thing is I used Prime95 on the CPU for over an hour and it didn't find any faults, but when I look at Task manager of all things, it's the CPU that is spiking!

I have updated every driver, flashed my bios, used different OS's just in case. I am out of ideas!

Any help would be appreciated!?

One more note, when I am monitoring the core speed on CPUz it jumps between 1600Mhz to 2400MHz in a split second. Don't know if that means anything.

CPU: Intel Core Duo E6600 @2.4GHz
Motherboard: Asus P5E x38 Chipset
RAM: 4Gb Micron Technology PC2-6400 400Mhz
Graphics: nvidia 8800GTS 320Mbps
PSU: Enermax Triathlor FC 650w
Audio: Soundblaster 24bit HD