Quote from: dannyst225 on January 23, 2014, 03:14:12 PM

i also got this issue,
im running 2x 1500 watt psu's on 4x Hd7990 Ati cards.
first time i booted the system it was running stable for two to three weeks everything worked fine.
and someday i came back cause my hashrate dropped to zero and checked the rig, cg miner reported temprature on gpu 1 511 degree and the rpm from gpu 3 & 4 was zero. so i checkt gpu 3 & 4 and the fans were running like they always do..

now everytime i boot my system up it runs stable for 10 - 30 mins and then the same thing happens gpu 1 511 degree
and fan speed of gpu 3 & 4 is zero, then windows freezes and then my rig shows a complete black screen and doesnt do anything anymore so i need to reboot the system and then everything works fine till a start cgminer and then after 10 - 30 mins the same thing happens.

Hi - did you solve your problem? I am experiencing this problem for the first time on a new rig build... seems to be always GPU 4 that flips to 511 and crashes the whole system... going to check risers, card, molex, PSU, again, but so far, they all appear to be in fine working order. Strange. Will try removing GPU 4 and see if anything else funny pops up..., or maybe I'll try it without a riser, right on the mb..

Any ideas welcome.