] The Intel Xeon processor introduces a new technology
] called Hyper-Threading (HT) that, to the operating
] system, makes a single processor behave like two logical
] processors. When enabled, the technology allows the
] processor to execute multiple threads simultaneously, in
] parallel within each processor, which can yield
] significant performance improvement. We set out to
] quantify just how much improvement you can expect to see.

Hyper-Threading speeds Linux