It's true that the bearings are smaller, but it certainly isn't creaky due to the plastic cups that surround the bearings. Incidentally neither of my Cannondales have a traditional BB30 and neither creak, but my friends CAAD X is one of the loudest bikes I've ever heard.
Funnily enough Cannondale can manufacture frames to their own tolerances. Creaking from dale frames will always be from fucked bearings or a botched installation and nothing to do with machining tolerances
surely that compromises on ball bearing size and presence of plastic in the cups = creaky