Im saying that a person who isnt smart enought to enter the bios to change the multi to 45+ and maybe raise the voltage a couple of notches wont be a person who uses a SR2 with 2 x5698 either.
So again, your scenario aint very realistic. There is no point in comparing 2 x5698 to stock clock SB, especially on this forum. OC'ed x5698 compared to OC'ed SB, but X5698 is a westmere, there aint that much headroom left, SB would beat it without trouble.
A few GB/s bandwith aint going to make much difference.

A gamer wont use 3-4 graphics card either for that matter, its kinda pointless since it it just gives you more hassle without any gains. 3-4 graphics card is just useful for some benching...