The question i have for you would be how much cheaper are those 5750's?
Your in AU right?
I can honestly say I have yet to see any real improvement with either an SLI or Crossfire set up. I have seen quite a few. If you read the FAQ for either SSLI or Crossfire they both state that they only offer improvement on a limited number of games made to use either technology and the only real benifit they offer to all games or apps is anti-aliasing. Spend your money on the newest most up to date single graphics card you can afford that will serve you better now and in the long run.
Crossfire is nice than one of course ,if two 5850 is cheaper ,I will choose Crossfire if I am you
I can honestly say I have yet to see any real improvement with either an SLI or Crossfire set up. I have seen quite a few. If you read the FAQ for either SSLI or Crossfire they both state that they only offer improvement on a limited number of games made to use either technology and the only real benifit they offer to all games or apps is anti-aliasing. Spend your money on the newest most up to date single graphics card you can afford that will serve you better now and in the long run.