^^^ If I had to guess (I'm guessing) your cards have crappy Voltage Regulator Modules, I'm guessing you bought the only cards available and they were still in stock because they suck.
I just got stuck with asus 580s elpida, same issue... i can pack 19 msi cards in one rig if I can find stock...
I got the cards a while ago, and I got them directly from the official distributor in my country where they can only sell at the original retail price.
I dont think any sapphire nitro+ limited edition are bad, they are all ASIC 80%+, samsung memory, and probably the best performance for mining.
The thing is, I tried to split the rig into 2x 6 cards each, and they work perfectly fine (the same cards I used in a 12 gpu rig),, but putting them into 1 mobo (tried ASUS B250 mining expert, Biostar TB250 btc pro, and Asrock h110 pro btc+), some cards crash, so Im guessing either claymore doesnt do well with 12 gpu rigs, or there is something Im missing.
I got plenty of virtual memory.
tried higher end processors and more ram
lowered core n memory
tried stock bios with stock core/memory and voltage
sgminer-gm works with 12 cards and all is fine, but it hashes lower than claymore for me (900hs for sgminer, 1050hs for claymore).
You need to segment the GPU's into groups of 6 using the command line flag. You then run two instances of the miner on the same rig. Works good that way.
