Stefan Mileschin

Apple's next iMac desktop could flaunt the company's "Retina Display" moniker, which stands for pixel density that matches that of your retina. Apple's idea of Retina display on a 20-something inch desktop is 5K, which is 5120 x 2880 pixels, or four times the resolution of WQHD (2560 x 1440), or sixteen times HD (1280 x 720). Early betas of Apple's OSX "Yosemite" feature references to display resolutions upwards of 5K, including 5760 x 3240, and 6400 x 3600.

At 27-inch, 5120 x 2880 would give the Mac a staggering 217 ppi of pixel density, which is not very far from the 263 ppi which 9.7-inch iPads offer, with their 2048 x 1536 resolutions. To put 217 ppi into perspective, a 28-inch Ultra HD display offers 157 ppi, and Apple's current 27-inch iMac with WQHD display offers just 108 ppi. A mainstream 24-inch full HD (1920 x 1080) display offers just 91 ppi. The GPUs that drive these next-gen iMacs are anyone's guess. Both current-generation AMD, and NVIDIA's new GTX 980 cap out at digital resolutions of 4096 x 2160.

http://www.techpowerup.com/206016/ap...k-display.html