Don't forget that AMD Hypertransport plays a strong role in system I/O latency. PCI-E interconnect using Hypertransport is very efficient.

Much of what users are seeing may not be directly CPU or memory related but rather... I/O based.

http://www.hypertransport.org/docs/w...ore_Design.pdf
http://www.hypertransport.org/docs/w...s_Parallel.pdf
http://www.hypertransport.org/