On Thursday 08 September 2005 10:49, Tony Schreiner wrote: > What is the maximum number of AMD64 cores supported by CentOS 4? While I know this doesn't help much in this context, and doesn't directly answer your question, indirectly it is relevant. The Gigaplane/UPA architecture of the Sun Enterprise XX00 (3000-6500) allows up to16 connections (in the 6X00; 8 connections in the E4X00 and E5X00)). Each pair of CPU's has local RAM on each UPA board (crossbar switched interconnect) that has a port on the Gigaplane bus (2.6GB/s throughput in the 83MHz version, 3.2GB/s at 100MHz), up to 15 CPU/memory boards plus one I/O board per E6500 chassis/Gigaplane, giving up to 30 CPU's and 60GB of RAM max). On this hardware, the 2.6 SPARC kernel is artificially limited to 24 processors; there seems to be stability issue over 24 CPU's. I'm burning in a 2.6.12 SPARC kernel (Corona from the Aurora project) on a 14x400 E6500 now (16GB of RAM). Oddly enough, the power requirements for this beast and for an octal Opteron are pretty matched, about 1.5KW or a little more. Certainly the 8x Opteron will be faster on many things; but under heavy multiuser load the 14-way SPARC does a surprisingly good job, with around three quarters the performance of a dual 3GHz Xeon (that outclasses the SPARC box in every way possible except interconnect) at a load average of 30 or so. At a load average of 30, the E6500 feels more responsive than my laptop (1.7GHz Pentium M) at a load average of 2. -- Lamar Owen Director of Information Technology Pisgah Astronomical Research Institute 1 PARI Drive Rosman, NC 28772 (828)862-5554 www.pari.edu