I ran a large trial of some Sun T1000's vs some non-SUN Xeon 3Ghz machines (16GB RAM), and a few AMDs. One thing that was clear very soon into the trial (apache web serving, r/o mysql access, php) was that the Intel and AMD kit was significantly faster with their response times (factors of 2-3) in the low end arena where only hundreds of simultaneous requests were made. But the T1000s began to really shine when the workload became intense, leaving the AMD & Intel kit for dead (literally in some of the trials). The x86 performance began to degrade quickly, yet the Sparc's with their magic thread/cores with 32GB RAM began to enjoy the massive load and respond very well, really perking up when the going got tough. We repeated the trial under Linux (originally Solaris10), and the same patterns were seen, although Linux was measurably worse overall (we didn't bother with Windows).

For Gazillions of requests, the Sparc's were measurably better, but they were poor in the low end throughput and response times (probably due to 1.2Ghz clock cycles vs 3Ghz). Those cores come into their own, especially with the RAM cycles being better taken care of than x86 can do.

For live, we installed x86 and the sparc behind load balancers. When the traffic is significant, they do more work than the x86 kit - thanks to the wonders of load balancers working out which responds best.