This logic board includes an Intel 1.6GHz i5 (i5-5250U) processor, 8GB onboard memory and heatsink attached. Versions of this board exist with and without SSD connector, and this board does not include the PCIe connector and cannot utilize Apple's blade SSDs. The Late 2015 iMac 21.5" was available with standard and Retina 4K LCD displays, but this board is only compatible with the standard display with 1920x1080 resolution, and only if the iMac originally included the 1.6GHz i5 processor option.
661-02884 Logic Board 1.6GHz (8GB) – HDD for iMac 21.5-inch Late 2015 A1418 MK442LL/A, MK442LL/A (820-00430) This is a replacement logic board for the Late 2015 iMac 21.5" non-Retina models that come with a hard disk drive.