Patriot Signature Line 4GB DDR3 1600 PC3 12800 Memory Module PSD34G160081H PC3-12800 (1600MHz) dual Data Rate 240-Pin Dual in-line memory module Non-ECC Unbuffered 7.8US Refresh Interval (8192 Cycles/64MS) 1.5V Power Requirement Auto and self Refresh capability Serial Presence-Detect (SPD) 100% Tested