nirrtix, can you run Firestrike, 3DMark11, etc. and post the URL results? I've recently tested a 970, already tested 980s, and 580s. Would be interesting to see how a 670 fits into the stack. The gap between 580 SLI and a 980 is often not that much (eg. 80 vs. 114fps for Unigine Heaven @ 1080p, Quality = High, Tesselation = Normal, 4x AA, 8X AF, NCP = Quality), so I suspect the difference between 670 SLI and a 970 could be surprisingly narrow in some cases (depends on the game, resolution, features used, etc.) I have some results
here (not added the 970 data yet); Unigine and CoJ are GPU-heavy, the rest are CPU variant, with X3TC being totally CPU dependent. Not yet written pages for all the 3DMark data I've gathered (under construction).