SLI 970 vs SLI 980, or other.

[epixoip]

First, you don't need -- nor do you want -- SLI. The fact that the title mentions SLI shows that you need to do some serious homework.

The 970 has the best perf/$, but if you can spare the extra $, then go with the 980 instead. Just be sure to buy reference design cards, not OEM design cards.