SLI- graphic cards

[Marinenachrichtendienst]

In jan. 2011 I bought this PC:

- Intel Core i7 Quad Processor i7-870
- Sapphire Radeon HD 6950 2GB GDDR5
- Corsair Vengeance DDR3 1600MHz 8GB CL9
- Corsair Vengeance DDR3 1600MHz 4GB CL9
- Corsair Vengeance DDR3 1600MHz 4GB CL9
- Gigabyte GA-P55A-UD4, Socket-1156
- Corsair TX 750W PSU
- NZXT Phantom Big Tower (white)
- Windows 7 - 64bit

(Broadband: 70mps/10mps)








My graphic card:

Sapphire Radeon HD 6950 2GB GDDR5
PCI-Express 2.0, 2xDVI, HDMI, 2xmini-DisplayPort


I'm considering buying the same card for sli, but the closest choice for a new card that are more or less similar to mine, is :

Sapphire Radeon HD 6950 2GB GDDR5
PCI-Express 2.1, 2xDVI, HDMI, DisplayPort, Dual Fan and BIOS


Question:

As far as I have found out, is that the only difference with these 2 cards, is the "PCI-Express 2,0" and the "PCI-Express 2,1".

So, if I buy the new graphic card, would they run smoothly together, or will there be any sort of complications ??

Thanks in advance !


PS! Maybe my card is more than enough for SH5, and only waste of money to buy a similar one ??