could be this?! I'm not sure about the i5 cores. http://www.youtube.com/watch?v=fUrnTzA3dSM&feature=related
NO because your clock is @ 2,8Ghz now you improved your CPU by your overwhelming intelligence... nonsense. It disabled one core and overclocked itself. It will do this depending on its tasks without you permission. what OS is that?
Yeah turbo boost is active. More so then the 1C/2T issue, why you didn't question why your 540M was at 2.8GHz. I think someone would have been more likely to notice that over the core/thread count.