What would happen if someone tried to put two different brands of PCI-E cards together like an MSI and an Albatron would they work? what about a 6600 GT and an 6800 together?
Currently no, tho iirc Nvidia is working to allow 2 different brands to work together in SLI. Second question, answer is no
you can run cards with different BIOS now AFAIK. They are working on running two different brands to run together in the furture too - I think that is slated for release 80. Second question... I can't answer that at the moment unfortunately.
From that, ( ) I'm guessing nvidia is working on being able to use different models with the same number of pixel pipelines in SLi with some sort of extra load balancing or a crossfire-like clockspeed cap? For example a 6800Ultra and a GT running at GT speed in SLi....anywhere near?