All monitors shut off , yet Pc still runs ? 6990 4 gig * Problem Fixed

hello,
I have a Weird problem I cant seem to diagnose, i have a 6990 4 gig and 3 Samsung bx2331 monitors..
my system is top of the line, randomly my monitors will just shut down, right before that happens, i hear a slight click and * I think a fan in my pc * specifically the graphics card fan shuts down , yet continues to run on default speeds. this will happen on random,
cant seem to pin point it..

it just happens randomly like the video card lost some voltage. or something.

my spec: all parts new and sent them in for testing. came back no issues.
t600 case
Gigabite 990fx board
6990 4 gig
1, 128 samsung ssds
4, 1.4 Tbite drives
850 watt gold edt Oz Psu
1090 t Amd 3.2 processor /w h80 water cooler
16 gig ram vengeance
basic Blue ray /dvd rom
torando cooler 220 fans etc
windows 7 ult

graphics drivers 12.11 beta Ati
tryed different drivers and doesnt make a difference
all other Pc drivers installed and up to date
checked all the monitors on different Pc.. monitors work fine..
swapped out the mini disply port cables and all monitor cables
Gpu, Cpu etc all runs cooler then overheat specs by 20-30 degrees

Can not pin point this , need some help..
Maybe Psu not supplying enough voltage ?
any other thoughts plz

Jayson
California