PR ratings and MHz

Firstly, is there a difference between "Barton MHz" and "T'bred MHz" ? I thought I saw somewhere that the 3000+ barton runs at 2167, but for the equivilent T'bred its about 2400, is this due to the core being substantially different, or am I just wrong!

Also on an OCed XP1700+ what speed would it have to be to qualify as a 3000+ ?

Yes, the PR rating is different slightly for Thoroughbreds and Bartons. No, they don't have completely different cores; it's just that the Barton has 512k cache over the Thoroughbred's 256k, as well as a higher default FSB which doesn't really matter for overclocking.

I'd say 2.2ghz or so would count as a 3000+... but why do you care?

Well, I was just curious about the most part, and when I OC my system, tt would be nice to know what it is equivilent too.