I have the memory now has not disappointed since a few weeks in operation and has been. I use 2x4GB in the 2011 Apple iMac (27 "i7, 6970M) in addition to the already built 2x2GB and the more power is clearly felt (total now 12GB DDR3). For memory hungry applications such as Final Cut X, Photoshop o. Ä. To get in regular 4GB often at the limit of what is possible, since the upgrade, however, you realize that it is still the work gives room for now. The Kingston ValueRAM was after installation immediately by Snow Leopard and also recognized Windows 7 via Boot Camp, and he is In contrast to the similar Samsung memory again a good deal cheaper. He has passed all stress tests and I would not hesitate to recommend him.