Display problems reoccuring with 2 dif GPUs

So Ive had my sigrig about 6 months. The other day, while the GPU is underload (video games for under 2 minuetes), the display started artifacting and flashing real fast and then my 2 monitors would lose signal and the screen would turn black. my computer would still be on all lights and fans and everything and I could still head the gpu fan (6870 very loud) spinning. I would be forced to hold the power button to restart the computer. any time i would try to game this would happen within 2 minutes but for normal use like web browsing and typical tasks everything would be fine. I filed an RMA with XFX saying the card was doing this and I sent it in, I ordered a gigabyte 7850 because i cant wait 2-3 weeks for XFX to send that back, i'll just sell it as refurbed..... and just got it 2 days ago and it has been fine so far, until...... today randomly while gaming (maybe for an hour) the same thing occurred... i restarted and kept gaming and there was no problem at all for about 3 or 4 hours. than randomly my screen fully artifacted and I still had a display output but the screen was striped in different shades of brown and tan. had to restart but everything is normal again.... GPU doesnt over heat, maxed out around 52*c and case is very well ventilated. everything is brand new from 6 months ago except the keyboard mouse and PSU are 2 years old. the GPU is 2 days old. i have most up to date drivers for the 7850. The 1 monitor is about a month old and the other monitor is 6 months old, but i definitely think GPU problem not monitor problem. After happening now I kind of have a feeling PSU is stressed, intermittently??? it is about 2 years old but ive never had problems before and it should be way more than enough to power a 7850, before that was a 6870 for the past 6 months and before that was a 4850 for 1.5 years.... any ideas or experience? is there a way to test any theories without having to waste more and more money.

like, no ATI drivers at all and then try gaming/stress test? if i dont have the drivers wouldnt windows switch to using the onboard graphics instead?
Edited by ryaan - 10/30/12 at 11:39am

well since it artifacted quickly before the screens went black with the 6870, i thought overheating maybe -- but it ran cool when i checked. i uninstalled drivers, driver sweeper, updated to most recent drivers off AMD website and it kept occuring. i tried increasing the fan speed manually to keep cooler - nothing changed. i underclocked it as low as it would go - i think 775mhz vs 900 default -- nothing changed. filed the RMA and just thought the card was defective. the 6870 used 2 6pin power adapters also but i never changed anything with that since I only have 2. the card was always seated right and the HSF was never touched and i assume seated tightly, but no signs of over heating.

next i received the 7850 and seated it and plugged the 1 power cord in that is needed. had already uninstalled previous drivers and driver sweeper before changing cards for a 2nd time... installed fresh most up to date drivers. runs cool in high 30s at idle and about 52* max load (well, while real world gaming). I havent done anything so far aside from post here, i am going to try using the other 6pin power cord though, but wouldnt those all be on the same rails on the PSU anyway? i can try using the 4pin molex to 6pin adapter they gave me instead, if maybe the prior cards stressed the psu + normal aging???


ps thanks for fast replies.

thats a good idea. im using mini display port to HDMI cables for my 2 monitors, i bought them on amazon for like 5$ each. they might be trash... i just got a response from XFX last night on the RMA

so i guess there was something wrong also, lol. but it hasnt happened since ive posted this luckily. if it does persist i will order new mini DP cables.
Edited by ryaan - 11/1/12 at 9:21am

happened twice more today. i changed cables for the GPU and also repositioned my PSU so it sucks air in from the case, not from under the case (it only has maybe 1/2 inche clearance which is carpet beneath the case.) i have a funny feeling it the PSU causing it.

replaced the PSU with a corsair TX 650. 2 days ago. problem occured today. Only thing I havent replaced is MOBO and CPU... just filed RMA with ASRock for RMA.