Wow this is awesome. Whats the main difference running two GPUs at x16 instead of both at x8? and can you run one at x16 and one at x8 (altough i doubt you can)
Both cards at x16 takes advantage of all the available (bus? been awhile since I looked into sli/cf) bandwidth. You can run with one in x16 and x8 as most of the mid range motherboards come with that configuration.