Product details
661-6637 4GB Memory, SODIMM, DDR3, 1600 rpm, A1278 for Macbook Pro NB-5606W
This is a 4GB PC3-12800 SODIMM memory stick. This is not officially supported by any Apple models until the 2012 updates. The 2011 quad-core models with the Sandy Bridge processors do detect the higher speed.
Apple part number: 661-6637
Compatible models: MacBook Pro (13-inch Mid 2012), A1278
661-6637 4GB Memory, SODIMM, DDR3, 1600 rpm, A1278 for Macbook Pro
This is a 4GB PC3-12800 SODIMM memory stick. This is not officially supported by any Apple models until the 2012 updates. The 2011 quad-core models with the Sandy Bridge processors do detect the higher speed.
Apple part number: 661-6637
Compatible models: MacBook Pro (13-inch Mid 2012), A1278
661-6637 4GB Memory, SODIMM, DDR3, 1600 rpm, A1278 for Macbook Pro