Hello, I am running one Asus 6990 and 6970 DC2 on my Asrock Z68 Extreme7 Gen3, I just install windows, all drivers and patches and updates.
In Catalyst Control Center, under CrossFireX, I found a GPU configuration allowing me to choose how many GPUs to use, the selections are 3 GPU (6 2 0) and 2 GPU (6 2)
I'm wondering what does the numbers in the brackets, could anyone help?

The Catalyst version is 11.10 Preview 3, running Win7 Pro 64bit