I've been experimenting with FileMaker 13's new "Perform Script on Server" (PSOS) script step to see how well it can be used to offload data-intensive tasks to the server. For example, to offload a SQL query (via the ExecuteSQL function) or a bulk update (using Replace Field Contents). The results that I'm getting are amazing.
When offloading SQL queries (with ExecuteSQL), the results are returned on average 20% to 50% more quickly.
Offloading bulk updates (with Replace Field Contents) is so much faster that its hard to believe. In one case, an update of a field across 33,000 records took 3 minutes and 30 seconds in FileMaker Pro, but took only 14 seconds when the update was pushed to FileMaker Server. And that same bulk update took less than a second with PSOS's "wait for completion" option unchecked.
If you're interested in the details, here they are: http://www.timdietrich.me/blog/filemaker-13-perform-script-on-server-insanity/