So there is apparently the older X-Series 650 and 750 and the newer tier of X-Series 560, 660, 760, and 850.
I'm confused about the differences (I only see a bit of difference on the -12v) and about why Newegg et al. are selling the the newer 560 and 850 but also the older 650 and 750, and they list the newer 660 and 760 as deactivated.
What's the deal? Marketing wizards are clearly at work!