Display1
21.5-inch display
1920×1080 resolution
21.5-inch Retina 4K display
4096×2304 resolution
27-inch Retina 5K display
5120×2880 resolution

Processor
Dual-core or quad-core
Intel Core i5
Quad-core Intel Core i5
Quad-core Intel Core i5

Memory
8GB
8GB
8GB

Storage2
1TB hard drive
1TB hard drive
1TB hard drive or
1TB or 2TB Fusion Drive

Graphics
Intel HD Graphics 6000 or
Intel Iris Pro Graphics 6200
Intel Iris Pro Graphics 6200
AMD Radeon R9 M380, M390 or
M395 with 2GB GDDR5

Wireless
802.11ac Wi-Fi
Bluetooth 4.0
802.11ac Wi-Fi
Bluetooth 4.0
802.11ac Wi-Fi
Bluetooth 4.0

Connections and Expansion
Two Thunderbolt 2 ports
Four USB 3 ports
SDXC card slot
Two Thunderbolt 2 ports
Four USB 3 ports
SDXC card slot
Two Thunderbolt 2 ports
Four USB 3 ports
SDXC card slot

Camera
FaceTime HD Camera
FaceTime HD Camera
FaceTime HD Camera

Keyboard and Mouse
Magic Keyboard
Magic Mouse 2
Magic Keyboard
Magic Mouse 2
Magic Keyboard
Magic Mouse 2

Features listed are standard configurations.
1. Display size is measured diagonally.
2. 1GB = 1 billion bytes and 1TB = 1 trillion bytes. Actual formatted capacity less.
TM and © 2015 Apple Inc. All rights reserved.