Turbo boost 2.0 (seems) to only be on haswell rigs, from what I've seen its only on mobile processors... Havn't seen the term used on a desktop processor yet, so if you're building a desktop rig be sure if you see turbo boost 2.0 that it isn't a mobile processor.
From what I saw whenI bought my laptop it seemed most of the Turbo boost were around .5~.6 ghz, and the 2.0 boot was 1ghz.