21.5-inch iMacs

The new 21.5-inch iMac, with Intel Ivy Bridge processors,  has two most significant changes, which are:

·       its thinner design,

                                            Top view: 2011 iMac (left) and new iMac (right)                   

·       And the option to upgrade to Apple’s Fusion Drive technology. 

the iMac has an aluminum case which reducing the width to just 5 mm at the edges. It has integrated a new anti-glare coating technology that lowers reflection without darkening the screen or affecting its color. The iMac even has a resolution of 1920 by 1080 pixels, and a gigabit ethernet port and a headphone/audio-out port on the back, and Thunderbolt ports. It also has been implemented with DD3 memory, a SDRAM module, of 8GB with a speed of 1600MHz. It brings, as well a L3 cache with 6MB of memory. Well, even having all these features it only weighs 7 pounds.

Left to right: Audio out, SDXC card slot, four USB 4 ports, two Thunderbolt ports, gigabit ethernet.

http://www.macworld.com/article/2018522/review-thin-is-in-with-new-21-5-inch-imacs-but-user-upgrades-superdrive-are-out.html