This time around, the improvement here comes in the form of a 500-nit backlight, translating to a super-bright screen that most users will want to tame down a few notches for daily use. The screen is brilliant and images appear sharp. The 4K Retina display is mostly the same as the previous version of the iMac, which, with its 4,096-by-2,304 resolution and stunning edge-to-edge glass, isn't necessarily a bad thing. Unfortunately, there's no easy way to use the iMac itself as an external display for a notebook or another desktop, like the Lenovo B50 or HP Envy 34 Curved can, since there are no HDMI-in or DisplayPort-in connectors.

The system can support up to two additional 4K monitors or one 5K display, including the internal 4K screen. Similar third-party adapters are available for DisplayPort and HDMI monitors. If you are carrying over Thunderbolt 2 accessories like external hard drives or displays, Apple sells a Thunderbolt 3-to-2 adapter for $49. They also mean faster and more versatile connections for data transfer. USB-C/Thunderbolt 3 ports are notable because they replace the older Thunderbolt 2 ports of the 2015 iMac and are becoming increasingly popular, even on Windows PCs. (Opens in a new window) Read Our Lenovo ThinkCentre X1 Review Despite the classic look, the stylish aluminum-and-glass iMac is still a design leader and more modern looking than the Lenovo B50, our last top pick for midrange AIO desktops, which is mostly black plastic. The design of the 21.5-inch iMac ($1,299.00 at Amazon) (Opens in a new window) is almost identical to the 2015 iteration, and at 17.7 by 20.8 by 6.9 inches (HWD), it's the same size. For artists on a budget or those whose daily tasks don't require a larger screen, the 21.5-inch with 4K Retina display (starts at $1,299 $1,499 as tested) is still the midrange AIO standard bearer, and is our Editors' Choice. Although the recent updates to Apple's smaller, more affordable AIO aren't revolutionary, it does get a nice bump in processor power, updated ports, the addition of discrete graphics, and a more-vibrant 4K display. The 21.5-inch model plays in an area without a lot of competition. With only minor updates to the iMac's design and components since 2012, Windows all-in-one desktops (AIOs) like the Microsoft Surface Studio have set their targets squarely on Apple's AIO, but most of those comparable models have larger screens and are priced well above $2,000, putting them more in line with the 27-inch iMac. Lacks HDMI-in and DisplayPort-in connectors.

Ports and SD card slot are on back panel.

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