We guaranty this kit will work in your machine. 2pcs. 4GB 1333MHz ECC REGISTER Module Genuine CMS brand, CMS is one of the most trusted names in the Computer Memory industry and this product carries a Lifetime Warranty from
CMS Max Memory: 128
GB Sockets: 16 sockets IBM System x3550 M2 4198-XXX IBM System x3550 M2 7946-XXX OUR DDR3-1333 modules automatically clock down to 1066MHz and 800MHz depending on which Intel Xeon model is installed and how many module Banks are populated. Due to chipset limitations, DDR3 Quad Rank memory is limited to operate at a maximum of 1066MHz. When two Quad Rank modules are installed per bank, the processor will automatically clock them down to 800MHz. System only supports (6) Quad Rank DIMMs per CPU or (12) Quad Rank DIMMs with two CPUs.