Take it your mining litecoins? Should of gone with a lower wattage cpu and single psu, you using risers to run these cards, also did you get the 280s in stock??? , my miner is using 2 7950s and 2 7970s I have a friend who runs a few of these rigs and has just setup a 280 rig and he said powerdraw and heat consumption is horrendous over the 7950s but there mining well at 24/7, if you want any tips give me a shout!!