Abstract—The second in the Niagara series of processors
(Niagara2) from Sun Microsystems is based on the power-efficient
chip multi-threading (CMT) architecture optimized for
Space, Watts (Power), and Performance (SWaP) [SWap Rating
= Performance (Space Power)]. It doubles the throughput
performance and performance/watt, and provides 10 improvement
in floating point throughput performance as compared
to UltraSPARC T1 (Niagara1). There are two 10 Gb Ethernet
ports on chip. Niagara2 has eight SPARC cores, each supporting
concurrent execution of eight threads for 64 threads total. Each
SPARC core has a Floating Point and Graphics unit and an
advanced Cryptographic unit which provides high enough bandwidth
to run the two 10 Gb Ethernet ports encrypted at wire
speeds. There is a 4 MB Level2 cache on chip. Each of the four
on-chip memory controllers controls two FBDIMM channels.
Niagara2 has 503 million transistors on a 342 mm2 die packaged
in a flip-chip glass ceramic package with 1831 pins. The chip is
built in Texas Instruments’ 65 nm 11LM triple-Vt CMOS process.
It operates at 1.4 GHz at 1.1 V and consumes 84 W.