Corsair Mac Memory Dual Channel DDR3 1x4GB Memory Key Features 4GB of DDR3 RAM Memory Speed of 1066MHz Designed for Macs and Macbooks Limited Lifetime Warranty Overview Corsair\'s 4GB Mac memory upgrade kit will help your system run faster and more efficiently. With hassle-free compatibility and renowned Corsair reliability and support, they are a smart performance investment. With a Mac that has been upgraded to the maximum amount of memory it supports, you will spend less time waiting for your applications to buffer data to the hard drive, and more time working or playing. Upgrading memory can also be a cost-effective way to get more life out of your older system before moving onto a brand new one.