The document compares the Lenovo ThinkServer RD350 and System x3550 M5 1U rack servers. Key differences include the RD350 supports Intel E5-2600 v3 CPUs up to 105W, has 2 PCIe slots, uses RAID adapters, and includes a 450W Gold power supply, while the x3550M5 supports up to 145W CPUs, has 3 PCIe slots, uses onboard RAID, and offers more storage configuration flexibility. Both servers offer redundant cooling and manageability features for reliability.