I have some Saphire R9 280x Vapour-x cards using these CGMiner settings, they give me 740Kh per card and run at 70 degrees.

cgminer --scrypt -o http://wdc.coinmine.pl:9090 -u username.1 -p x --lookup-gap 2 --thread-concurrency 11200 -g 2 -I 13 -w 256 --auto-fan --gpu-fan 30-75 --temp-cutoff 90 --temp-overheat 85 --temp-target 72 --gpu-memclock 1500 --gpu-engine 1080 --gpu-powertune -20 --expiry 1 --scan-time 1 --queue 0 --no-submit-stale