I wrote recently about Ben Zorn’s benchmarks.  And now I’ve just found out about a web page with performance comparisons of JVM and CLR implementations:  Kazuyuki Shudo who has been posting for many years performance comparisons of various JVMs has now added CLR and Mono for two of the benchmarks that have versions in both C# and Java.  The complete set of benchmark results is at http://www.shudo.net/jit/perf but most benchmarks are Java only.  If you’re interested in the CLR or Mono, look at Linpack and Eratosthenes Sieve.  These results are for the existing version of the CLR (1.1) and hopefully our new version (2.0) will have an even better performance.