4GB Upgrade for a Dell OptiPlex 780 Mini Tower System (DDR3 PC3-12800, NON-ECC, ) 240-pin DIMM DDR3-1600 DDR3 PC3-12800 Unbuffered, NON-ECC, DDR3-1600, 1.5V, 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