Dragonfly and Hyperthreading....

[Tom Hummel]

    Nobody is going to purposefully idle
    resources just to make HT work more efficiently because that would
    destroy UP performance.
I didn't mean it that way. Intel first idled cpu resources to achieve 
higher clock rates. Then they recognized they needed to use those clock 
cycles better, because netburst won't achieve 10Ghz. Something they 
counted on. So the "solution" was a hastily implemented HT.

. ..tom

P.S. thanks for the other info