Patriot Signature 4GB DDR3 PC3-12800 (1600MHz) CL11 DIMM Memory Module PSD34G160081 100% tested PC3-12800 (1600MHz) dual Data Rate 240-Pin Dual in-line memory module Non-ECC Unbuffered 7.8US Refresh Interval (8192 CY CLES/64MS) 1.5V Power Requirement Auto and self refresh capability Serial Presence-Detect (SPD)