I've been hitting the limit of my VPS's (virtual private server) 256mb RAM limit since installing CivicSpace, and I keep adjusting the php limit to try to avoid having forked processes fail, but then CivicSpace will fail on certain admin pages.
I now understand that when looking at the module activate/deactivate page it loads *every* module installed, even if it's not activated. (For other pages it only loads activated modules.) Since CivicSpace includes so many modules, this almost guarantees I'm going to run out of php memory if I have the limit set at 20mb or 16mb, and that's about the same range where I bump my head on the server privvmpages limit given my current configuration.
I don't think I've had this problem with Drupal yet, but I probably will as I keep adding modules.
As a temporary fix I'm going to remove modules that aren't used and aren't likely to be used. For a more permanent fix I'm going to pay more to get a higher RAM configuration. Instead of just picking 384mb or 512mb I'd like to look into how I want Apache, MySQL and PHP tuned and figure out how much RAM should be dedicated to each. I might also setup my own test box and run stress tests on Drupal with various configurations. Then I'll know my RAM target.