./cgminer.exe --scrypt -o (yourpool) -u (user) -p (password) -I 13 -g 2 --thread-concurrency 8193 --gpu-engine 1050 --gpu-memclock 1500 --temp-target 73 --auto-fan

You must undervolt your card to 1.075V using a modded bios to achieve these temps.
Take a look at cryptobadger's guide or search the forums for undervolting guides.

heres the link: hxxp://www.cryptobadger.com/2013/12/radeon-r9-280x-gpu-mining-results/

Also, there might be an optimized bios for your cards on this thread: hxxps://litecointalk.org/index.php?topic=12369.0