Interesting, got two 280x on Win7x64 w/14.9 drivers.  Getting about 147k on each card but nothing ever found on card #2, only HW errors?

Swap back over to known good sgminer cfg for DRK and bam, GPU 1 working solid.  Latest gpu support was for cgminer 3.7.2 and this ver is 3.7.5.  Anyone have any ideas?