Thanks!
The video cards are using a full EK setup. The CPU is using a Koolance 380i. Radiators are SR1 Classifieds dual pass 360mm/480mm with the pumps going at full tilt 5/5. Fans are ceramic and serrated/knife edged.
I am using my own ROM's for the cards, my own modified 13.12 drivers and a very specific CL/BIN file for CGMiner 3.7.3. I get about 1150KH/s from each card in full stable 24/7 mining. I have taken it as far as 1200KH/s per card, but only tested it for a few hours.
Never had a chance to do much long term testing on it at 1200KH/s. I rent this rig out to people for mining. I usually promise them 4,000 KH/s but they get an average of 4500/4600KH/s when mining.