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is it worth paying a bit more for the 7850?
unless you have a 69x0 to CF with, may as well get the 7850
The 6950 can still be unlocked to 6970 right?
highly unlikely with a new card (might be possible with an older 2nd hand one)
The Msi 6970 is faster than a 7850 and still around £200
http://www.overclockers.co.uk/showproduct.php?prodid=GX-123-MS