Comparing Solaris and Linux on the same system
There is an interesting article at geekpatrol: Sun Ultra 20 M2 Linux Performance with an comparison of Linux and Solaris. Overall Solaris leads by wide margin. As every benchmark this has to be taken with a large grain of salt as it tests the whole package of operating system and the compiler. So you can´t know exactly the influence of the operating system and of the compiler. But in the end it´s the package that counts.