There have been lots of rumors swirling around about the possibility of a new 21 inch iMac with a 4K Retina display emerging some time very soon.
Given that the only Apple device to come close to this resolution is the even higher-fidelity 27-inch iMac with Retina 5K display, it’s likely this new retina device could be the smaller 21.5-inch iMac.
The latest beta of OS X El Capitan tells us more about an upcoming iMac that features a smaller 21.5-inch display with a 4K resolution — an insane 4096 x 2304 display to be exact. This new display means that you will be able to watch a 4K video in its native resolution, without having to scale it down — video professionals will love this.
As for pricing, we can expect the new 21.5 inch iMac to definitely cost more than the current HD version’s $1,099 price tag!
Source: http://www.techradar.com