Wintec ONE MHzCL9&nbsp; 4GB(2x2GB) UDIMM Kit 2Rx8 1.5V with HS 4 Dual Channel Kit DDR3 1600 (PC3 12800) 240-Pin SDRAM 3OH16009U8H-4GK DDR3 memory type; a modern memory standard that raises the level in memory processing performance 4GB total memory; the product provides an abundant memory capacity for an effective system tasks management 2 memory modules; they share the number of system tasks among themselves, so one module doesn't get overcrowded