Upgrading from 560ti 1GB sli to gtx 760 and have a question

I have a pair of EVGA GTX560Ti FPB's in SLI in an i7-2600k, also have a EVGA GTX670FTW Sig2 in an i7-2600k. The GTX670 is a bit faster than the GTX760, if you look at the passmark scores. Not a bunch, and for the price difference, probably not worth it (the 670 is more expensive).

Just some observations

power consumption, actual wattage used is MUCH less with the single 670 vs the sli 560. FPS is right there with each one, different situations in the same game will produce different results in FPS. It's almost as if, the more intense it gets, the 670 will have the edge, but just lolly gagging around, the SLI will have slightly better fps. I noticed no discernible difference in temps when going SLI. Both PC's are built using the same case, one has an air cooled CPU, the other is on water. The SLI machine is actually quite a bit more silent, I haven't done much poking around about this, but the fan noise in the 670 case is more noticeable. It's nothing annoying, but I do hear the difference (both are on desktop, opposite sides of monitor).

The 670, when pushed in benchmark, will run right around 300 watts usage. The sli 560's will run around 430 watts. I know people squeal about mega wattage, I run 850 watts in each machine, and as you can see, I'm not pushing either power supply. xbit labs has a nice article on this, I'm not trying to talk you out of a mega watt psu, but gpu's are getting much more efficient than they used to be. CPU's too. BTW, both machines are OC'd to 4.4GHz.