In one of the SQL Server sessions at last week's Microsoft Technical Roadshow, Michael Platt showed the first three minutes or so from an MSDN Channel 9 video. In it, we saw one of the systems at Microsoft's labs in Redmond where ISVs and OEMs assist the SQL Server team with their performance testing and benchmarking - an HP Integrity Superdome system with 64 64-bit Intel Itanium 2 CPUs, 1Tb of RAM and a couple of thousand 18.2Gb disks. Why so many small disks? Apparently it's about providing provide parallel reading capacity to increase the overall system throughput and hence run the CPUs at their limits.
The whole system cost in the region of $5.1m and the full details of the benchmark tests may be found on the transaction processing performance council website.
Interestingly, one of the problems encountered during the benchmarking was running out of power to spin up all of the disks and having to install a new power distribution unit at a cost of $250,000!