The 8286-42A server supports up to 4TB of IBM POWER8 memory features in 16 CDIMM slots for two socket processor DCM systems, or 1TB maximum memory for single socket processor systems. IBM POWER8 memory for all 8286-42A system models must be installed in identical pairs, but can be of different sizes from other memory pairs. The IBM 4794 Power Active Memory Expansion Enablement feature enables memory expansion on the 8286-42A system, providing compression and decompression of data in memory which expands the maximum memory capacity for additional processing capacity and better performance. IBM POWER8 Memory uses both buffered DDR3 or DDR4 DIMMs, which have the same 1600 MHz speed, use the same L4 cache and the same memory controller. All IBM POWER8 memory is in used or refurbished condition, includes warranty, free technical support by phone or email and is guaranteed for IBM maintenance contracts.