> And remember that it is well known that Solaris does not shine with
> one or 2 CPUs.

I don't agree. If you have a specific case where Solaris is not
performing well on one or two CPUs, please file a bug at
http://bugs.opensolaris.org.

It is possible some of the performance differences are due to the
gcc version being used as Solaris bundles gcc 3.4.3 and other distros
may bundle 4.x, but it is much more likely due to the default ABI
used by the bundled gcc. "gcc -O" on Solaris will default to ia32/x87,
whereas on the other "64 bit" distros tested it will default to amd64.
The performance difference can be seen in the two Byte Computational
benchmarks on page 7 where Solaris appears to lag: Dhrystone 2
(./Run dhry2) and Floating-Point Arithmetic (./Run float). These
tests are compiled with "gcc -O" which produces ia32/x87 code.
When adding "-m64" which puts Solaris on par with the other distros,
the performance jumps quite a bit. Measured on a Intel QX6700,
dhry2 goes from 9307771.4 to 13421763.5 and float goes from
707932.5 to 1477185.6.

The ABI used can make a big difference. Solaris allows you to
choose either, but the default for the bundled gcc is still the
slower ia32/x87.