I read a paper recently that basically said 'about a dozen threads' is optimal for most workloads. If they can deliver 12 'real' threads then the hyperthreads a

I read a paper recently that basically said 'about a dozen threads' is optimal for most workloads. If they can deliver 12 'real' threads then the hyperthreads are redundant. Also, last time I checked (late penryn) the branch prediction and other elements necessary for good HT take up egregious amounts of die space -- which can probably be put to better use.