8GB Kit (4GBx2) Upgrade for a Apple iMac (21.5 and 27-inch, Mid 2010) System (DDR3 PC3-10600, Non-ECC,) 204-pin SODIMM DDR3-1333 DDR3 PC3-10600 Unbuffered, NON-ECC, DDR3-1333, 1.35V, 512Meg x 64 The only brand of memory upgrade available directly from a DRAM manufacturer, tested to meet the most stringent industry specifications Install it yourself in about 15 minutes. The same top-quality memory that the worlds largest computer manufacturers install in the systems they sell