Problem with CGminer and Radeon 5970

[honorthebtc]

I have a nvidia GTX 670 as device 0, main GPU that i don't want to mine with,
and a Radeon 5970 as device 1, with a dummy plug. (this GPU has 2 cores)

i use the command line : cgminer --scrypt -d 1 -I 10 -o "pool infos"

When i run the .bat, the cgminer screen goes black.
On GPU-Z, i see that one core of the 5970 is working, but the other core is at 0%.

CGminer : 3.7.2
SDK 2.9 (also tried 2.6)
Catalyst 13.11
Windows 8.1 64bit

CGminer worked great with only the Nvidia GTX 670 plugged in (low hash rate but everything was working).

Can anyone help me? I want the GPU to work on both core ofc. Thanks

EDIT : The problem would be the same even if i wasn't scrypt mining...

[vm1990]

use gui miner scrypt alpha. its easier to work with. change amd drivers to 12.8 or 13.1