McGarr wrote:

A hyperthreaded P4 is not two cpus, it just uses execution units where
they would ordinarily be idle, but it will not run "twice as fast". HT
is good for multitasking as it uses makes more of the processer
avaliable, but for example many gamers disable HT to achieve better
performance.
So i personally wouldn't run it as two seperate processes.

Very true except for the example for s@h WUs.

Where Intel's HT does work well is for certain special tasks where the HT overcomes the deep-pipelining bottlenecks in the P4 design.

s@h is one application that can gain an increase in overall throughput for running two WUs at a time. The individual WUs take longer, but you get more WUs done overall over the day.

Happy crunchin',
Martin