PerformanceWiki [the blog]

The following are performance benchmark Web pages from major DBMS and hardware vendors:

Microsoft SQL Server 2008. Example of performance highlight and resource page
http://www.microsoft.com/sqlserver/2008/en/us/performance-scale.aspx  
(includes overview, plus links to benchmark results, papers, and more)

Oracle. Benchmark result pages
http://www.oracle.com/solutions/performance_scalability/index.html

Microsoft SQL Server 2008. Benchmark result pages
http://www.microsoft.com/sqlserver/2008/en/us/benchmarks.aspx

Microsoft SQL Server 2005. Benchmark result pages
http://www.microsoft.com/sqlserver/2005/en/us/benchmarks.aspx

Microsoft SQL Server 2003. Benchmark result pages
http://www.microsoft.com/windowsserver2003/evaluation/performance/benchmarks/default.mspx

Hardware vendors IBM xSeries Benchmark News
http://www-03.ibm.com/systems/x/resources/benchmarks/intel/news/index.html

IBM Power Systems
performance benchmark
http://www-03.ibm.com/systems/power/hardware/benchmarks/index.html

HP - http://h71028.www7.hp.com/integrity/cache/393900-0-0-0-121.html.pw.