Niagara 2 (formally the UltraSparc T2) was a big step forward for Sun Microsystems’ chip multithreading (CMT) efforts. It’s not that there was anything really wrong with its Niagara 1 predecessor, but 90-nanometer process technology imposed some fairly severe restrictions on what could be crammed into each of the eight cores. As a result, Niagara 1 was well-suited for a relatively narrow range of network-facing workloads. Niagara 2, by contrast, was able to leverage 65nm process technology to spread its wings considerably–which it did by significantly beefing up the threading, floating point, and other capabilities of the individual cores, in addition to adding on-chip I/O.

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