This 64GB memory is 100% compatible with Fujitsu CELSIUS R940 (D3358). Information on memory configurationThe following technical specifications should be observed in advance:RDIMM and RDIMM 3DS (Registered DIMM) or LRDIMM and LRDIMM 3DS (Load Reduced DIMM) RAM memory can be installed in the device. LRDIMM memories are recommended if large memory capacities are to be achieved.RDIMM and RDIMM 3DS memory modules cannot be operated together with LRDIMM and LRDIMM 3DS main memories.If a memory expansion is to be carried out with the existing RAM memories, it must be checked which basic memory technology (RDIMM / LRDIMM) is available.Memory slots for which no processor is available must not be fitted; if memory modules are offered with higher clock rates than specified by the system, the memory clock is automatically adjusted to the system specifications.Memory for Intel Xeon CPUs:CPU / SystemRDIMMLRDIMM Xeon E5-16xx v3Xeon E5-26xx v3Xeon E5-46xx v38GB RDIMM16GB RDIMM32GB RDIMM64GB RDIMM DDP128GB RDIMM 3DS256GB RDIMM 3DS32GB LRDIMM64GB LRDIMM DDP128GB LRDIMM DDP128GB LRDIMM 3DS256GB LRDIMM 3DS