Apple says that the display in this 4K iMac, as well as the revision to the 5K iMac that was announced the same day, offers an expanded color space. Thanks to new red-green phosphor LEDs, the displays can display a wider range of red and green light than before, allowing them to display 25 percent more colors.
In a demo at Apple, I was able to detect subtle differences. The new displays can offer more color detail and more vibrancy than the display on the older 5K iMac models. I’m a little red-green color blind, and even I could detect the differences. If you work in graphics or video, you’ll probably be happy to have access to a display that’s capable of displaying 99 percent of the P3 color space. But for most people buying the 4K iMac, the real difference will be the mind-blowing jump to Retina.
Besides this, it’s worth noting that all the 21.5-inch iMacs, including this one, use Intel Broadwell processors. The 27-inch iMacs, on the other hand, use newer Skylake processors, which should provide improved performance.
As a side note, reading Jason’s reviews I’ve found out that the new accessories require Bluetooth 4.0 to work, so my Early-2008 iMac is not compatible with them. Perhaps it’s finally time to buy a new iMac, after all.