Axiom 4GB DDR3-1600 ECC RDIMM for IBM # 49Y1558, 49Y1559, 39U4459 - 4 GB - DDR3 SDRAM - 1600 MHz DDR3-1600/PC3-12800 - ECC - Registered - 240-pin - DIMM

Up to 1600 MHz speed with Registered signal for playing the latest games and using heavy software 4 GB memory smoothly executes complex apps and games 240-pin-pin DDR3-1600/PC3-12800 operates at an effective bus speed with minimal power consumption and as a result, you get optimal computer performance with an improved memory heat dissipation