The Sun Enterprise 420R server is four-processor workgroup server for network computing based on the UltraSPARC processor technology. This next-generation workgroup server brings multiprocessing power, UltraSCSI disks, and the industry-standard peripheral component interconnect (PCI) I/O bus to a highly modular, rack optimized 4RU (rack unit) design.The Sun Enterprise 420R server gives customers the flexibility to scale their processing needs without wasting precious space, making it an ideal server for service providers, financial institutions, compute-intensive environments, or anyone who needs strong processing power in a small footprint. Sun's commitment to high-performance computing means the Sun Enterprise 420R server delivers increasing levels of industry-leading performance that users expect from Sun servers, while at the same time preserving 100 percent binary compatibility with application software.This product allows the upgrade of SPARCserver 20, 10, 4, or 5 to Enterprise 420R server base configuration with one power supply and 32X CD-ROM. After the upgrade the customer must return complete SPARC server including CPU, memory and drives.