With microprocessors capable of over one billion calculations per second—less than one nanosecond per operation—fast memory access time is critical in achieving balanced, sustained performance on technical workloads. Data crosses over an SGI NUMAlink switch, round-trip, in as little as 50 nanoseconds—less time than it takes a beam of light to travel 50 feet—compared to 10,000 nanoseconds or more with many commodity clustering interconnects. Furthermore, SGI NUMAlink technology is the only interconnect that provides global shared memory between cluster nodes.

The industry-leading performance of NUMAlink interconnect technology is clear when comparing bandwidth and latency characteristics to other interconnects (Table 1). This translates into better system performance in MPI applications as well as industry standard system benchmarks, such as Linpack (Table 2).

Table 1 - Latency and Bandwidth performance of common interconnect technologies

Bandwidth per link citations are from the following sources:

1. http://www.cray.com/products/xd1/index.html#RapidArrayInterconnect
2. http://doc.quadrics.com/Quadrics/QuadricsHome.nsf/DisplayPages/ 81DD13F71CFD762580256EAD0010AA75/$File/Performance.pdf
3. http://nowlab.cis.ohio-state.edu/projects/mpi-iba/
4. http://publib-b.boulder.ibm.com/Redbooks.nsf/f338d71ccde39f08852568dd006f956d/55258945787 \ efc2e85256db00051980a?OpenDocument
5. http://www.myricom.com/myrinet/performance/
6. http://www-1.ibm.com/servers/eserver/pseries/hardware/whitepapers/sp_switch_perf.pdf

Table 2 - Comparison of Linpack system efficiencies in the November 2004 Top 500 list

* Linpack Rmax/Rpeak for 256P systems listed on November, 2004 Top 500 list - see www.top500.org