Finished binning my PSC a little while ago and I feel I should clarify this -- high voltage scaling on PSC is just a matter of the settings you run. Roughly speaking, running tight but with loose tRCD gives the most voltage headroom. Sticks that take 2.2, 2.3, and even 2.5V are the exception, not the norm (and usually suck anyway ). I will make a post in more detail at some point.
Quick binning at 2800C9 isn't enough, evidently. I'm currently working on rebinning with my PSC binning chip and, aside from better voltage across the board as is to be expected with a better quality IMC, high frequency (2800++) voltage scaling is dramatically better, 100mV+ lower in some cases versus the poor quality 4670K I used some time ago. Naturally binning stringently is always better (though, you know, having some validation that your goals are realistic is always the problem), I would bet some kind of 2850+, 2900+ metric for IMC binning is a better idea.
(Though, technically, this IMC would have failed my Samsung binning, it needs +0.3 IOD for 2800+, unlike with PSC)