Offtopic: sketch, he's a she.

I'm sure sooner or later, Gwynne or someone else will come forward and "debunk" common myths with thorough evidence, benchmarks and/or discussion of precise details but I don't see a problem with Gwynne not doing that in her Google Groups message.

Hopefully the big G will add more pages on the subject of PHP optimisation, perhaps in collaboration with members of the PHP Group, which cover the more usual performance problems, solutions and tips encountered which can really make a substantial difference.