Peculiar Reboot Problem

[CharismaRise]

Hi guys,

I've recently built the following system:

ASUS Crossfire IV Formula
AMD Phenom II x6 1090T 3.2GHz ( Running stock)
8Gb G.SKILL Rip Jaw
ASUS ENGTX480 1536Mb
OCZ stealthxstream 2 ultra-silent 700W
Cooler Master HAF932 Full Tower
Seagate 2TB Green 5400RPM (storage)
Western Digital 500Gb Blue 7200RPM (primary)

Windows 7 Enterprise SP1 64bit

I'm having an issue that under heavy load (crysis 2/Mafia 2 etc), the computer would randomly reboot.

Here is what I was able to investigate:

CPU temp under heavy load: 42-54C
GPU temp under heavy load: 70-85C
VCore 1.36-1.44V (fluctuating)
DRAM: 1.65V
CPU/NB: 1.18V
SB: 1.10V
NB:1.10V

I've ran memtest86 for a few hours and it gave no errors. I thought it might be my video card so I ran 3D Mark Vantage and it went through just fine. I then ran prime95 and Bingo! Computer rebooted almost instantly. Sometimes I run prime95 and it lasts for 2-5 mins but thats about it. Turning off the "restart on crash" still didn't let me see the error - reboots.

I was thinking either my power supply is unable to supply proper rail current or my motherboard is faulty.

Please advice as I'm really getting desperate with this problem!

Thank you!

 

[vigilante212]

OCZ stealthxstream 2 ultra-silent 700W (these are known to go bad)