  The BaBar experiment is the particle detector at the PEP-II B-factory
facility at the Stanford Linear Accelerator Center. During the summer shutdown
2002 the BaBar Event Building and Level-3 trigger farm were upgraded from 60
Sun Ultra-5 machines and 100MBit/s Ethernet to 50 Dual-CPU 1.4GHz Pentium-III
systems with Gigabit Ethernet. Combined with an upgrade to Gigabit Ethernet on
the source side and a major feature extraction software speedup, this pushes
the performance of the BaBar event builder and L3 filter to 5.5kHz at current
background levels, almost three times the original design rate of 2kHz. For our
specific application the new farm provides 8.5 times the CPU power of the old
system.
