OWC 4.0GB 1600 MHz DDR3 Memory

DDR3 1600 MHz SO-DIMM Memory for iMac 27" with Retina 5K Display, 3.5 GHz/4.0 GHz i5/i7 (Oct 14), iMac 27" 3.2/3.4/3.5 GHz i5/i7 (Sep 13)

OWC memory is designed specifically for compatibility with your Mac. You start with the highest quality components and then create memory that meets the high speed, capacity and programming specifications of nearly every upgradeable Apple computer. The result is JEDEC-compliant memory that's perfect for a faster Mac.

OWC memory is hand inspected and tested for quality at every step of the manufacturing process. But that's not all. OWC owns and maintains state-of-the-art facilities where nearly every Mac made in the last two decades has been manufactured. That's because OWC doesn't just test relentlessly for quality and reliability. They test in real-world machines to ensure that OWC memory is optimised to deliver a lifetime of superior performance in your Mac.
That's the OWC difference.