The iMac \"Core i5\" 2.8 21.5-Inch Aluminum (Late 2015/Broadwell) features a 14-nm \"Broadwell\" Quad Core 2.8 GHz Intel \"Core i5\" processor (5575R) with four independent processor \"cores\" on a single chip, a 4 MB shared level 3 cache, 8 GB of onboard 1867 MHz LPDDR3 SDRAM (which could be upgraded to 16 GB at the time of order, but cannot be upgraded after system purchase at all).
The iMac "Core i5" 2.8 21.5-Inch Aluminum (Late 2015/Broadwell) features a 14-nm "Broadwell" Quad Core 2.8 GHz Intel "Core i5" processor (5575R) with four independent processor "cores" on a single chip, a 4 MB shared level 3 cache, 8 GB of onboard 1867 MHz LPDDR3 SDRAM (which could be upgraded to 16 GB at the time of order, but cannot be upgraded after system purchase at all), 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" 1920x1080 LED-backlit 16:9 widescreen IPS display with a fully laminated glass cover and an anti-reflective coating. 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.
Compared to its predecessor, this model essentially has the same external enclosure, but it has a more advanced architecture and graphics architecture.
The "Late 2015" iMac models shipped with a compact aluminum Apple Magic Keyboard and the choice of either a multi-touch "Magic Mouse 2" or a traditional wired Apple mouse. For an additional US$50, one also could upgrade from the Magic Mouse 2 to the "Magic Trackpad 2," which provides multi-touch and pressure-sensitive "Force Touch" capabilities.