Craig,
I think the best and the simple method would be to divide database as per manufacturer.Because very often the name of the microprocessor suggest their main feature (87,89 family of CPU's).Arranging database as per various parameters like frequencies will confuse the whole matter.
Moreover , any new feature which is introduced in CPU's are strongly advertised by the manufacturer itself.
And moreover , such database is nice to have and not must,more important in such database will be to see all possible manufacturers and cpu's.But if I am looking for something special I would always prefer to check manufacturer site rather than to rely on such database and its update.