I'm a little bit confused by contradictous infos about that,
on your page http://www.intel.com/support/processors/corei5/sb/CS-032278.htm it tells me 2.8Ghz,
but i've seen on retailers website that 1 Core can run up to 3.3Ghz on its own.
Just to get rid of any doubt, could you confirm this info ?
I would suggest checking this link:
This processor can run up to 3.3 GHz with Turbo Boost enabled, but keep in mind that the turbo bust cannot be manually set, this feature is controlled by the operating system and any running software, so the feature will be used only when the operating system determines that it is needed.
This feature is normally used by the operating system when the system is running heavy applications like 3D games or 3D design, but it is not the run.