I don't know that anyone here will have any experience with this, but....

A coworker of mine is attempting to set up SquirrelMail under RedHat. When he uses the PHP RPM, everything's good, except there's a bug in the version of PHP they've packaged up, so he goes to compile it himself. When he does that, PHP's performance goes down the pooper. So he tried recompiling the source RPM for the one RedHat ships. And it's performance is bad.

So that would tend to point to a compiler performance issue, since the source RPM should compile with the same options as they used for the binary RPM.

Has anyone else encountered this and found a solution?