A new line of iMacs with ultra high-resolution Retina Displays is in late testing stages within Apple, according to our sources who have used the future desktop computer. While the machine will sport a thin profile similar to that of the current design, which was introduced in 2012, it will be packed with new internals such as faster processors and improved WiFi antennas. The fact that the iMac is in late testing indicates that Apple could be preparing to launch it alongside OS X Yosemite this fall. The Retina iMac will mark Apple’s first foray into Retina desktop computers. Apple first launched the Retina display with the iPhone 4 in 2010, expanded it to the iPad in early 2012, and brought the screen to the Mac with Retina MacBook Pros in late-2012. As for the resolution of the new Retina iMac, OS X Yosemite betas include references to 6400 x 3600, 5760×3240, and 4096×2304 resolution screens.