SLI or getting 1 better card when GPU gets too old

When my GTX560Ti gets old, will it be best to get a better GPU and throw the GTX560Ti away or get a new GTX560Ti and SLI it with my old one?

Cost-wise it seems SLI should be cheaper, but I don't know performance wise.

sli is very competitive performance-to-$$$ wise, *IF* your computer is already ready for it; that is, you have a suitable mobo (which generally cost a good amount more than a non-sli mobo), you have a capable PSU (again, more $$$), and your cooling is sufficient (you get the pattern).

lets assume you have all those things set in place. there're still quite a good amount of things that work against an sli setup vs a single GPU config.

- sli is more dependent upon drivers for performance. whereas single GPU gentlemen see new drivers yield performance gains (while old drivers still work reasonably well at worst), sli lads might see a game rendered unplayable by old drivers at worst; new drivers may fix the issue, but without a proper 'sli profile', raw performance may not be where it should be at. all in all, this isnt to say sli driver support is bad, its actually fairly robust, but sli can be much more of a headache than a single GPU config

- micro-stutter. was an issue, still may be an issue, not sure. sounds annoying as hell though.

- cooling is negatively affected. so you have an overclocked gtx560ti and you want to throw in another? think both cards will run at the frequencies of your single gtx560ti? maybe, but probably not.

so those are some raw issues with sli.

when ditching your old GPU and simply replacing it with new single GPU, you generally also get new technology. this can range from improved raw image quality, new AA methods, new v-sync stuff (gtx 680 in particular here), etc.

all things to consider.

what games to you play? This will be the tell tale.