If you are running a recent version of APC with Sugar, you may have seen the following errors:
Potential cache slam averted for key 'foo' in /Users/hobodave/foo.php on line 3.
This is due to a change in the default setting for the apc.slam_defense setting in APC 3.1.4 to enable it by default. You can read more about it here.
You can easily revert back to the old setting by adding this to your php.ini file:
This should make all of those errors go away.