SLI or new card

[crisis uk]

I've recently bought a new monitor which displays at a resolution of 2560 x 1440 and have noticed a reduction in performance when gaming at this level (obviously).

What I'm wondering is if I would be better off going for another GTX 670 2GB to run in SLI or getting a new card, say a GTX 770 4GB?

Would I benefit more from the extra card or would the extra memory serve me better at this higher resolution?

As far as I understand it is better to have more memory on your GPU when it comes to larger resolutions/multi monitor setups or would the performance gain from running in SLI outweigh getting a new single card with more memory

Thanks

 

[keynes]

You will get better performance from a 2nd GTX 670, the higher VRAM is more beneficial and significant at higher resolution than 2560x1440.

 

[crisis uk]

Thanks for the info, I'll look into getting another 670 then.