PC crash, can't find the cause

[monster64]

My PC crashes when I playing a game or running at maximum load. For example when I run rthdribl and prime 95 small ffts it crashes always within 10 mins. I have a venice @ 2700 mhz and a 6800 GT @ 420/1120. Now if I run prime 95 small ffts alone, it is stable for 12 hours, I never really went longer. Nothing is overheating that has a temp sensor. Also I can run rthdribl or loops of 3dmark 05 for 12 hours and it is also stable. Its only when they are running together do I get the crash. I know what you are thinking, it's my PSU. Well although it only has 18A on the 12v rail, I used a voltmeter to measure the rails and I simulated the crash and the rails held up steady. If my PC really wasn't getting enough amps, then the voltage on the rails would drop significantly right before the crash, but it doesn't. Its not my ram as I ram it at at 122mhz with timings of 3-4-4-8 and it still crashed. I still think its my PSU, but I can't prove it. Any way I can directly measure the amps on the 12v rail, just to make sure? I know how to do it, but where on the mobo would I measure it? Any help would be greatly appreciated.

 

[RichUK]

When you say ?where on the motherboard can this be tested? .. are you referring to which pins on the 20/24 pin motherboard power connector, if so im not sure on that one maybe pins 2 and 4, this is relay switch that initially turns on the power supply.

I would imagine that you can test the amperes/voltage strength on the molex power connector, using the yellow as live and the adjacent black power cable as ground as this is drawing off of the 12 volt rail.. the same can be tested for the 5 volt rail using wires red and the adjacent black cable.

 

[monster64]

I did test the 12/5v rails on a molex connector and the 3.3v rail on a different connector (not sure what kind it was.) You can't just test for amps off the molex connector too or am I wrong?

 

[RichUK]

http://dansdata.com/images/top686p6/woundup800.jpg

the above picture shows each rail being tested as you can see .. although looking at that picture they are only testing the voltage for each rail .. you can change the volt meter to measure the amps being produced as well, and then you can measure both amps and voltage.

 

[JEDIYoda]

I seriously doubt its your PSU!
Yiou have bought hook line and sinker into the inferior PSU propaganda!!

Yet you haven`t told us the brand or the specs on your PSU!!
If your using a 2 year old PSU with say 350 watts etc...then I might consider your PSU.

But as it is there just too many more things that could be happening besides the PSU!!

 

[monster64]

Full system specs:

AMD 3500+ venice @ 2700 MHz 1.55v (245x11) w/ XP-90 (max temp-52C)
ASUS A8N-SLI (245 fsb, x4 multi = 980 HTT)
Geil PC4000 1GB 1:1 @ 245 MHz 2.5-3-3-7-1T 2.85v (rated 2.6v-3.1v)
XFX 6800 GT @ 420/1120 (Stable all the way up to 440/1150) w/ V1 (max temp-72C, 2 fans)
Fortron 530W 20 pin 2 fan PSU (3.3v-28A 5v-40A 12v-18A)
Maxtor DiamondMax Plus 9 160GB IDE
Audigy 2 Value sound card
4 80mm case fans+1 side air duct
Toshiba DVD-RW combo drive

Again, Prime 95/rthdribl alone are stable, for 12 hours each, but crash when run together and games crash too.