21.5" IPS DisplayWhether your iMac is in your studio, living room, or kitchen, the display is the focal point. With a 1920 x 1080 screen resolution and a 16:9 aspect ratio, you'll be able to playback Full HD 1080p content natively. The IPS panel allows for wider viewing angles so more people can enjoy the display without having to crowd around it. With integrated Intel Iris Pro Graphics 6200, the iMac delivers Full HD visual effects and 3D graphics. The iMac simultaneously supports full native resolution on the built-in display and up to a 4096 x 2304 resolution on an external display.5th-Gen Broadwell Intel Core i5 Quad-Core PerformanceThe iMac houses a 5th-Gen Broadwell Intel Core i5 Quad-Core processor. Its quad cores can reach a stock speed of 2.8 GHz. It can also be overclocked up to 3.3 GHz, thanks to Intel Turbo Boost 2.0 technology. The 5th-gen Broadwell Intel processor uses low voltage for better energy efficiency while still providing fast performance. Combined with 8GB of 1867 MHz LPDDR3 onboard RAM, the iMac allows you to multitask quickly and efficiently.Thin DesignThe iMac maintains its 5mm profile, which is up to 40 percent less volume than the 2011 iMac. Using an advanced welding method called friction-stir welding, Apple was able to join the front and the back of the iMac together directly.802.11ac Wi-Fi & Bluetooth 4.0With three-stream 802.11ac technology, the iMac takes desktop Wi‑Fi speeds over the top. When it's connected to an 802.11ac base station - including AirPort Extreme and AirPort Time Capsule (both sold separately) - you can reach data rates of up to 1.3 Gbps. That's triple the previous 802.11n standard, which means you'll get up to three times faster Wi‑Fi. You also get double the channel bandwidth, with 80 MHz-wide channels providing more room for more data to flow faster than ever. Bluetooth 4.0 wireless technology is also built in, so you can connect accessories such as a wireless keyboard and mouse.Thunderbolt 2Expand the capabilities of your Mac. Connect high-performance peripherals. Transfer data at high speed. Even daisy-chain multiple devices. And the iMac with Retina 4K display has Thunderbolt 2, delivering twice the bandwidth - up to 20 Gbps - for fast data transfers. While the Thunderbolt 2 ports double as mini DisplayPorts, the iMac with Retina 4K display cannot be used as a standalone monitor like its predecessor. It can, however, be used simultaneously with an external display and can output up to a 3840 by 2160 resolution.USB 3.0With USB 3.0, you can transfer large files in seconds instead of minutes. Every iMac comes with four USB 3.0 ports - with speeds up to 10 times faster than USB 2.0 - and you can connect all your USB-compatible devices, including your iPhone, iPad, iPod or digital camera.