"Siebel is one of the epidemic applications in the enterprise. Look in any company of a certain size and you find Siebel or a similar application. Customer Relationship Management was one of the big hype topics a few years ago. Thus benchmarks for this application are really important for server vendors.
When you dig around in the benchmark whitepapers for Siebel, you will find a really interesting gem of information: You can outperform three IBM p570 p6 4,7 GHz with two Sun Sparc Enterprise T5120 and two T5220.
According to the the benchmarking document from Oracle and IBM a configuration consisting out of one 8-proc p570, one 4-proc p570 and one 2-proc p570 was benchmarked. This configuration was able to serve 7000 users with a rate of 106,157 business transactions per hour. A few days ago Oracle certified the benchmark for our UltraSPARC T2 base servers. According to this document, a configuration consisting out of 4 systems with one UltraSPARC T2 each was able to serve 10000 users with a rate of 142,061 business transactions per hour.
I want to add some perspective to this result: The result is especially interesting, as the IBM Power6 based configuration is vastly more expensive than the one based on UltraSPARC T2. The capabilties of the T2 are really amazing."
[highlights introduced by me]
Update: more details