IBM 90Y3109 8GB DDR3 PC3-12800 1600MHZ
8GB (1x8GB, 2Rx4, 1.5V) PC3-12800 CL11 ECC DDR3 1600MHz LP RDIMM for M4
For IBM X3550M4/X3630M4/X3300M4/X3500M4/X3650M4