A 6950 will run 3 monitors in eyefinity - 2 off of the 2*DVI, for the third you will need an active displayport adapter DVI -> DP or active displayport adapter DVI -> mDP depending on the adapters that come with your card, to connect the mini displayport on the 6950 to your DVI monitor. (this is assuming that you are running 3 DVI monitors). The only 6950 that natively supports 3*DVI monitors is the Sapphire Flex edition 6950.
I'm running an MSI 6950 TF3 with triple monitors atm. I don't game much, have only really played COD Black Ops, played fine, but as I said, don't really game much atm.