[jpstewart]

There are many variables that come into play when benchmarking machines.  Keep in mind that something like Blender might not be very well optimized for SPARC at the source code level.  Plus the compiler used might not be producing particularly well optimized machine code from that source.  You might get different results using a different compiler (e.g., Sun Studio might outperform GCC) or benchmarking software that was written specifically for SPARC.  Those are just two possible reasons for the disappointing performance you've witnessed....

In addition to that, it's possible (even likely) that the SPARC CPUs weren't used for their performance, especially not in the era of your machine.  Earlier SPARC systems than your V880 performed well compared to their contemporaries, from what I've heard.  After that some sites continued to use SPARC simply because that's what they were familiar with.  

A lot of money was invested in the overall architecture of the machines to build reliable systems for the data centre, and the Solaris OS was built to match.  So some sites would choose SPARC and Solaris not for raw performance but for reliability reasons.