If you have tested cards one by one without any problem, then try to swap riser and slot, and you still having same problem with same slot different card, your problem could be PSU molex issue, although you have enough power in total, but each single molex has maximum power output only.
I don't think it's the issue here. I got 3 cables powering 6 risers. so 2 risers for 1 cable i did that because i read somewhere not to power more than 2 risers if you don't want it to crash.
The errors i get are drivers ones.
here is the problem:
when i let the rig on and mining, at one point i get this :
http://imageshack.com/a/img924/8324/GOew4p.jpgand/or this :
http://imageshack.com/a/img922/1346/KgYv9J.pngIt's hard to screen because when miner crashes, it's laggy as fuck. It takes me like 3 to 5 minutes just to save the screenshot... next time i'm gonna use my phone and take pictures of my screen like a fucking retard
, way faster than waiting for nothing.
what is the temperature of the room?
it's about 20°C, nothing too hot. Rig is in an open frame i did myself. Cards are between 60-65°. I'm gonna place 6 80mm fans i got when the rig will be set and good to work. I also plan on adding a 7th card, a R9 290 i got earlier, got a space for it but i wanna be sure PSU can handle it so i didn't placed it yet (and i also need to buy PCIE extender slots and a PSU cable cause it's a 8+6 pins).
here's a picture of my rig:
http://imageshack.com/a/img922/16/nprG5Z.jpg
