[NewsPoster]

[Correction: fixed error in revealed native resolution] The recently-released sixth developer beta (just today matched with a fourth public preview) has revealed listings for an as-yet-unreleased product listing, which could be an iMac -- and, according to the configuration files inside the beta, the forthcoming unit sports a "professional level" 4K resolution of 4096x2304 -- slightly higher than "consumer 4K" resolutions of 3840x2160 found on most 4K HDTVs. The files refer only to resolution, and give no hints on display size or class of product.

Current speculation favors the new resolution being fitted on a new model of 21.5-inch iMac, creating a Retina and non-Retina model for each of Apple's current two sizes of the all-in-one desktop, though the reasoning behind doing so remains murky. The files indicated that the resolution can be scaled up to 5K, which could suggest a cost-cutting replacement panel for the current 5K Retina iMac. If the displaywere for a 21.5 iMac, the 4K resolution in a 21.5-inch diagonal screen would offer a pixel-per-inch count of approximately 218, identical to the pixel density seen on the 27-inch 5K iMac.

It's unclear when the referred-to product could be released, but the earliest it could appear in September or early October, the projected window for the next iPhone and iPad models as well as for the next major upgrades to both OS X and iOS. It's also possible that the 4K resolution device could be something entirely different, from a revised Retina MacBook Pro to a new Thunderbolt Display to the long-rumored but never-seen Apple HDTV, among other possibilities.

It is also possible that Apple has either a new screen size for one of its existing products in mind, or that the mystery 4K display is for some new product entirely. The lack of any 21.5-inch 4K displays on the market currently may be a hint that whatever product Apple has in mind would not use that size, but instead utilize some other display dimensions.

An earlier version of this article incorrectly stated the native resolution of the mystery device, giving it a 4:3 ratio rather than the 16:9 ration the graphic shows. MacNN apologizes for the error.

[SDLeary]

This is roughly a 4:3 aspect screen. Probably an iPad; perhaps the rumored iPad Pro (12 inch)??

SDLeary

[Salty]

I thought that was weird, that it'd be a 4:3. Sure enough though I punched that into a graphics app and it looks pretty 4:3. So yeah I'm betting iPad that runs OS X? Maybe something else that needs to be retina quality but 4:3 works with? Perhaps an iPad that dual boots OS X and iOS (okay that seems far fetched. More likely runs iOS apps on top of OS X ... but that seems more than a little inefficient. Though perhaps one can hook this iPad up to a Mac (by USB-C?) and use it as a drawing tablet?

[SDLeary]

I don't think it would run OS X, but could run as a secondary monitor either by cable or AirPlay. There are already apps that allow this with current iPads.

SDLeary

[Mike Wuerthele]

We had a GIANT conversation about this behind the scenes yesterday. We've got no idea either - all we've got is data lines in pre-release software, and a placeholder icon.

[chimaera]

Were did you come up with the 4096x3048 numbers? The data lines shown all appear to be 16:9 ratios, including a 4096x2304 line. If it is 16:9 rather than 4:3, then a mid-sized iMac display makes sense.

[Charles Martin]

chimaera: good catch. We think one of the media reports originally had the bad figure, and later corrected it, but we dutifully copied the bad info at the time. The graphic included in the story shows the "native" resolution of the 5K iMac and the 4K product (second listed resolution in each case), and clearly we got it wrong. We've corrected the story. Thanks for letting us know.

[DiabloConQueso]

My guess is that it's a new Thunderbolt Cinema Display with Retina resolution.

[Mike Wuerthele]

Diablo, this is my guess as well.