iMac 21.5-inch (Aluminum) 2.9GHZ Quad Core i5 (Late 2012). - Apple MD094LL/A. Used cheap refurbished iMac 'Core i5' 2.9 21.5-Inch Aluminum (Late 2012) features a 22 nm Quad Core 2.9 GHz Intel 'Core i5' I5-3470S (Ivy Bridge) processor with four independent processor cores on a single chip. Customize your hard drive, memory, and optional external optical drive. It also has a NVIDIA GeForce GT 650M graphics processor with 512 MB of dedicated GDDR5 memory, built-in 'FaceTime HD' webcam and stereo speakers.