Open your config.wtf and add the following line:

SET timingMethod "1"

or

SET timingMethod "2"

And you should see the same speed-up. My guess is that there is a setting that changes something that produces the increased performance, but making it a default change would result in lots of calls to tech support, as a few people who tried the change experienced crashes and freezes, and others reported no improvement in performance.

So it looks like one of those things that could help a lot of people, but could also screw up a lot of people, so they leave it off and keep shut about it. But if a player finds out and tells everyone...