I have one GTX480 and one GTX285.
At the very beginning, device0 is GTX480 and device1 is GTX285. However, I exchanged the pci slot position of the two cards. But when running ./deviceQuery, I find that device0 is still GTX480.
I want the default one is GTX285. But it seems that the squence of cards does not depend on the squence of pci slot.