Hi! I am trying to run a computation-intensive app on 4 GPUs on two HD5970 cards - using CAL.
In default configuration, CAL reports only one device, and indeed allows only one device to be set up.
When crossfire is enabled, I can run two devices, but performance is degraded (instead of getting double the speed, I get about half the speed).
As the threads are independent, I don't need crossfire - I just need to run on all four GPUs - as many threads as possible concurrently.
I was not able to configure the system so tha CAL reports 4 devices, and no crossfire.
O/S: Ubuntu 10.4, kernel 2.6.32-21-generic
Mobo: Asus 6PT