Athlon 2500+ Strange Problem

[YoungBlood]

Wondering if anyone could shed some light on a strange CPU issue i've been having over the last few days.
I play a certain online game which I know will allways max out the CPU usage at 100% constantly, however recently it will drop to about 7% causing the game to lock up for a few seconds then return to 100%.
Sure enough few seconds/minutes later it does it again, usage drops down and game locks up, then returns to 100% and all is rosey.

Its a clean install of XP with no other process's running in the background that should'nt be. CPU temps in BIOS show around 60C.

Another strange thing is 3dmark 06 will give 1fps readout on the cpu 3d tests and eventerly the machine reboots, ive not beable to complete a 3dmark 06 run on there yet.
MBoard is a Gigabyte GA-7DX

any help appriciated

 

[YoungBlood]

3D card is a 6600GT, im guessing with a base CPU temp of 60C with the standard AMD fan that when it gets to the CPU tests of 3DMark it shuts itself down for self preservation.
All drivers are up to date afaik.
One thing I didn't mention in my 1st post is that prior to this the PSU let go, with a bang and smoke and everything. I replaced it with a "cheap" 400watt as the system is not worth spending big bucks on, maybe something got damaged along the way.
Its just abit of a mystery why the CPU goes into, almost idol at random intervals, i'll put it down to a damaged CPU from the PSU letting go if nobody has any other suggestions.

 

[YoungBlood]

Cheap as in £15 "sumvision" 400watt
Voltages are Vcore 1.69
+3.3V = 3.26
+5V = 4.91
+12V = 12.80

Thoes are straight from the hardware monitor in the bios

 

[YoungBlood]

Yeah 3dmark 2001 runs fine, I think I might have sussed the problem out.....Could it of just been that the CPU was causing a bottleneck with that 3Dcard.
I placed an old Geforce 4 Ti4200 in there and all was rosy. Maybe the CPU was no match for the Geforce 6600GT that I put in there. Or it could be that the 6600GT draws too much power from my cheap PSU and causing problems that way.....
Also the mbm link u posted was broken but i'll google it up

Nope your link is the same as the google link, guess it's down for now

 

[YoungBlood]

The problem that I was having with the CPU dropping off during games has stopped since downgrading the 3DCard, so im going to assume that it was just some sort of bottleneck.
Thanks for the mirror'd link split, that one works and i'll post some numbers after work.

 

[YoungBlood]

£8.45, I feel robbed lol
It was a matter of conviniance, I needed a new PSU there and then and they only stock cheap stuff. I shall upgrade the PSU then hopefully the 6600GT will run smoothly with the 2500+ Athlon.
One thing I will say though is that I have had 2 of these cheap PSU's literaly go bang which has put me off leaving the PC on while asleep/at work.
The more expensive ones, im looking at a thermatake or ocz brand im assuming have some sort of protection so your house does'nt burn down if they let go. Luckily when these cheap ones have died I was there to pull the plugs out fast, as you do

thanks for your help spilt and co