This is it: the holy Retina grail. We can skip simulated modes scaled down to 4K panels — this is a true 27-inch Retina display. I’ve been assuming that this wouldn’t be possible to bring to market for a couple more years, and I couldn’t be happier to be wrong. $2500 is a fair price if it works.1
The big question, assuming Dell actually ships this thing and it doesn’t have some horrible flaw, is whether it can run at full resolution, in 2X mode, at 60 Hz, treated as a single screen from a Mac Pro.
A single Thunderbolt 2 bus doesn’t have enough bandwidth. It needs to use multiple cables plugged into two separate buses, meaning the only Mac today that it could even work with is the current Mac Pro. You’d need to plug it into only certain port combinations to have it span two buses, and we don’t actually have any idea if the GPUs and OS X would treat it properly.
Fortunately, we don’t need only this specific one to work as a Mac Retina display. If Dell can ship a panel like this, so can others. And maybe a 27” Retina iMac at $2999 isn’t out of the question for this winter.