i finally compiled a cgminer 3.7.2 with scrypt-jane patch based on the cachecoin thread.
gotta love scrypt-jane. It makes my reference 290x about 5c cooler than scrypt / scrypt-n mining.

https://lh3.googleusercontent.com/-5lv4lYVt980/Uw0Ym_rbrdI/AAAAAAAAGmo/4ouOQeCEuMs/w713-h449-no/thor_290x.jpg

setting:
-g 1 -w 256  --lookup-gap 2 -I 20 --thread-concurrency 33792  --gpu-engine 937 --gpu-memclock 1250