In addition to updated internals, the display on the new 2015 iMac is now better than ever.Apple will still sell the 1,920 x 1,080 21.5-inch iMac, at $1,099 and $1,299 configurations.But in graphics tests, I found I got better performance from the GPU on the new iMac than last year's model. The Magic Trackpad 2 gets a complete overhaul. Wider color gamut The late-2015 iMac features a … As long as you're running OS X El Capitan, the machine will automatically pair to your accessory, no entering of codes needed.The Magic Mouse 2 looks the same as the old Magic Mouse — at least until you turn it over. Adding the feature to the Magic Trackpad 2 is a big step in helping Force Touch adoption.Apple took the arrival of the new iMac to update its accessory line. That makes some sense because that machine, which had Intel's Haswell architecture, was clocked at 3.5GHz.All in all, the new iMac is a solid upgrade that starts at an even lower price. It has the same insanely high-resolution (5,120 x 2,880) display and the same port configuration that includes four USB 3.0 ports, two Thunderbolt 2 ports and gigabit Ethernet.Along with the new iMac, Apple has updated its wireless keyboard, mouse and trackpad accessoriesThe model we tested came with a 3.2GHz Intel Core i5 processor with 8GB of RAM, an AMD Radeon R9 M390 graphics card with 2GB of RAM and a 1TB Fusion Drive for storage. Force Touch has the potential to be a user-experience paradigm on the desktop the same way 3D Touch is becoming one on mobile. The bottom no longer has a battery door, it just has a Lightning port — as well as new feet that are designed to move better around your desktop surface.The outer design of the 27-inch iMac is the same as last year. If you've ever owned a wireless Apple accessory, you've probably invested in some rechargeable AA batteries and have experienced the annoyance of having to track down an extra battery just so you could finish your work.The rechargeable battery means the Magic Keyboard has a slightly lower incline.The good news for new iMac buyers is that in 2015, all 27-inch iMac computers come with the 5K display.The Magic Trackpad 2 has 30% more surface area, is white and supports Force Touch.The display is the heart and soul of the 27-inch iMac, and it's the reason you'll want to buy this machine. Although we would recommend not buying the $1,799 model (spend the extra $200 for a better GPU and the Fusion Drive), simply because non-SSDs make us cry — it's still amazing that such a great display in such a powerful machine is at this price point.The 5K iMac remains the best all-in-one on the market, and in 2015 it gets an even better display and — even better — a lower price.The late-2015 iMac features a wider color gamut which means there are 25% more colors available to display.