280x = 4.4M each
Care to share your settings? Im getting about 3.25 on each card. Using the sgminer in the op.
setx GPU_MAX_ALLOC_PERCENT 100
setx GPU_USE_SYNC_OBJECTS 1
sgminer --kernel fresh -o stratum+tcp://axr.suprnova.cc:2020 -u Rage19420.0 -p x -w 256 -I 15 -g 2 --thread-concurrency 8192 --temp-cutoff 85 --lookup-gap 2