I have finally decided to pull out the old Nvidia hd 7900 x2

They were good cards back in the day, but they are severely outdated.

After some research, my first natural choice was the Nvidia 275 which performed reasonably better than the Radeon 4890 in field tests
newegg.com/Product/Product.aspx?Item=N82E16814130475
newegg.com/Product/Product.aspx?Item=N82E16814150359


However... I am having second thoughts about going with the Nvidia 275 due to the launch of windows 7 and directX 11

From what I understand, only cards capable of running directX 10.1 will be supported by directX 11

(The Nvidia card is not, the Radeon is)

That being said, would it be a wise choice to buy the Nvidia 275 knowing that it will not be supported by directX 11?

Theydifference in performance is nominal. Get the GTX 275 only if you are using high res like 1920 by 1200 or something. Save the $30. i have that exact card(XFX 4890) by the way and it oc's wonderfully. Stock in 850 MHz and i have it at 970 MHz

The 275 just edges ahead in performance terms, i wouldnt worry about the direct x 11 issue too much, as by the time it becomes mainstream both cards should be prettty much outdated.

there is some time for dx11.but if u r realy concerned u can go with ati.

As a side note, there is always physx compatibility issues aswell. Though im not really sure if ati cards can "do" physx yet?

I would be more concerned about case size, cooling, power, and fit rather than choice.