best gpu card for x58a-ud3r board?

[Störung]

Hello,

I think I will have to buy a new videocard, there I have problems with fans of both my GTX460. One card one fan hardly turns around and it hardly starts to run of itself, I can't use this as topcard because it. The other card has a fan that seems to hit something when it starts to run above 2750rpm, lost already 3 blades. It rattles also very annoyingly at high rpm. Though I cannot see that it hits something, I think it must be the bottom card.

But what GTX do I take best now with this board since nowadays cards are PCIe 3.0 and my mb doesn't support that.
Waist to get GTX660? Or will it work anyways only not as fast as when it would be in a PCIe3.0 lane?

Any help on this pls
THX!

[Störung]

Ok; seems last night the bad fan of the top card came loose and probably hit the bottom card since there are only 5 blades left :p
Didn't wake me up; only could find one blade back though that was on the floor outside the case?!

Anyways, I got the coolingblock of the card and am thinking to take the good fan of the broken fan card and replace it  with the bad turning fan on the card that is left over.
Maybe afterwards I can find a new cooler for the card or attach computerfans on the heatsinks; will see if it works.

Still advice about possible new card to buy is welcome.