PC SPECS:
DUAL CORE 2 EXTREME
X2 1GIG KINGSTON GAMING RAM
X2 X1900 CROSSFIRE CARDS
RAID 1 SATA DRIVES



symptoms:
computer would run all day as long as I did not play any graphic intense video games. Call of duty 4 would reboot my pc either as soon as the 3d engine started or within 20-30 minutes.
things I checked... temp issues first.. monitored temp using everest and found temp was reasonable. Temp rose on GPU's and on CPU but not out of controll.

took one of my vid cards out to see if it helped... nothing... swapped in other vid card by itself... nothing.

swapped memory sticks in same fashion.

only thing left was my Power Supply. Even though voltages checked out across the board.

Power supply fixed the problem! evidently it was crapping out under heavy load of graphic intense games with my ATI crossfire setup.

HI welcome to PCHF

The PSU is the foundation your PC is built on... adequate wattage-rating and solid performance from a good quality maker are necessities for gaming performance.
Nice troubleshooting-- glad you got it sorted

thank you for the complement! As much as I am giddy I found it on the first hardware purchase, I posted it so people with simular problems may benifit from my two days of wracking my brain!

evidently systemax put top quality components in my rig when purchased... And I mean top notch. nothing OEM. but after removing the powersuply upone swapping I discovered that the powersupply choice they used was definitely the weak link.

I worked a couple years as an electronic tek and used to troubleshoot power supplies for medical equipment and it was quite common to have one that ran fine under a minimal load... but under stress would fail.

However... It was also my understanding that booting up was the most stressful thing a computer goes through... But that did not take into account the stress a good 3d engine can do

Gaming is far harder-- because it is sustained pressure on everything.
Boot is stressful --but only lasts a minute
Gamers will go for days sometimes...and that's maxed out.
Stresses CPU/Video-card/RAM/ Motherboard/ Cooling / PSU/ Monitor
want to read about hardware --and how people beat on it ?

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bords, try to use windowsXP or upgrade your pc then change the hard disk...