A Web page on the AMD site compares the cut-down Duron chip to Intel's cut down Pentium Celeron processors in a competitive comparison and the first category picked on is, yes, you got it clock speeds.
According to the site, "faster clock speeds typically deliver improved application performance", but this is surely no longer part of AMD's public pronouncement.
These days AMD says that real world application performance doesn't depend on raw clock speeds and has gone through a number of loops explaining this in detail to anyone who will listen.
The message does not yet appear to have totally trickled down within the organisation, however.
You can find the defective AMD page here. µ