This introduced the 64-bit UltraSPARC processor and in later versions, lower-cost PC-derived technology, such as the PCI and ATA buses (the initial Ultra 1 and 2 models retained the SBus of their predecessors).

The SPARC-based Ultra 3 Mobile Workstation laptop was released in 2005 as well, but it would prove to be a short-lived design and was retired the next year.

In October 2008, Sun discontinued all these, effectively ending the production of SPARC architecture workstations.

Note: the Enterprise 220R is an Ultra 60 motherboard in a rack-mountable server chassis with hot-swappable power supplies.

The A60 Ultra 3 mobile workstation rebadged the Tadpole SPARCle (550 and 650 MHz) and Viper (1.2 GHz) laptops.