-Display Retina 4K display 21.5-inch (diagonal) Retina 4K display 4096-by-2304 resolution with support for one billion colors 500 nits brightness Wide color (P3) -Processor 3.0GHz 3.0GHz quad‑core Intel Core i5 (Turbo Boost up to 3.5GHz) Configurable to 3.6GHz quad-core Intel Core i7 (Turbo Boost up to 4.2GHz) 3.4GHz 3.4GHz quad-core Intel Core i5 (Turbo Boost up to 3.8GHz) Configurable to 3.6GHz quad-core Intel Core i7 (Turbo Boost up to 4.2GHz) -Memory 3.0GHz 8GB of 2400MHz DDR4 memory Configurable to 16GB 3.4GHz 8GB of 2400MHz DDR4 memory Configurable to 16GB or 32GB -Storage1 3.0GHz 1TB (5400-rpm) hard drive Configurable to 1TB Fusion Drive or 256GB or 512GB SSD 3.4GHz 1TB Fusion Drive Configurable to 256GB, 512GB, or 1TB SSD Graphics 3.0GHz Radeon Pro 555 with 2GB of VRAM 3.4GHz Radeon Pro 560 with 4GB of VRAM Video Support and Camera FaceTime HD camera Simultaneously supports full native resolution on the built-in display at millions of colors (21.5-inch) or 1 billion colors (21.5-inch 4K) and: One 5120‑by‑2880 (5K) external display at 60Hz with support for 1 billion colors, or Two 3840-by-2160 (4K UHD) external displays at 60Hz with support for 1 billion colors, or Two 4096‑by‑2304 (4K) external displays at 60Hz with support for millions of colors Thunderbolt 3 digital video output Native DisplayPort output over USB‑C Thunderbolt 2, HDMI, DVI, and VGA output supported using adapters (sold separately) Audio Stereo speakers Microphone 3.5 mm headphone jack Support for Apple iPhone headset with microphone Connections and Expansion 3.5 mm headphone jack SDXC card slot Four USB 3 ports (compatible with USB 2) Two Thunderbolt 3 (USB-C) ports with support for: DisplayPort Thunderbolt (up to 40 Gbps) USB 3.1 Gen 2 (up to 10 Gbps) Thunderbolt 2, HDMI, DVI, and VGA supported using adapters (sold separately) 10/100/1000BASE-T Gigabit Ethernet (RJ-45 connector) Kensington lock slot