The iMac Core i5 3.1 21.5-Inch Aluminum (Retina 4K, Late 2015/Broadwell) features a 14-nm Broadwell Quad Core 3.1 GHz Intel Core i5 processor (5675R) with four independent processor cores on a single chip, a 4 MB shared level 3 cache, 8 GB of onboard 1867 MHz LPDDR3 SDRAM , a 1 TB (5400 RPM) hard drive, and an integrated Intel Iris Pro 6200 graphics processor that shares system memory. It also has a built-in FaceTime HD webcam and stereo speakers. This model has a 21.5 4096x2304 LED-backlit 16:9 widescreen IPS DCI-P3 Retina 4K display (that runs pixel doubled to look like 2048x1152). The rear of the case is aluminum and is thicker in the middle and tapers to a razor thin 5 mm at the edges. Connectivity includes four USB 3.0 ports, dual Thunderbolt 2 ports, Gigabit Ethernet, 802.11ac Wi-Fi (802.11a/b/g/n compatible), and Bluetooth 4.0.