There is a being released this week to increase this timeout automatically. (So you can wait for the weekly, or change the php setting now).
Re: Upgrading to 3.2 is slow as molasses and not rendering properly
by Damyon Wiese -
Number of replies: 0
It is slow the first time a page loads because it now compiles the stylesheets. If you are on a under-powered server you might need to increase your php max_execution_time to 300.