Enterprise performance and flexibility. Compact footprint. ThinkSystem ST550 is a 4U tower server that provides the performance and reliability you expect from the data center, delivered in a package optimized for office environments. ST550 supports Lenovo AnyBay technology which enables the mixing of storage types (U.2/SAS/SATA) in the same bays. Up to 6x PCIe adapter slots and multiple RAID options offer the flexibility you need for NICs, GPUs, and other adapters.