HT technology is introduced in newer P-4's
HT stands for Hyper Threading, means that some applications, that suport multi threading (like photoshop, adobe premiere, 3D studio max) distributes the works into two lanes. so gets full benefit from this HT technology,
so, in actual your CPU is 1, but other works as a Virtual CPU on your system.
this enhances the speed of processor execution of programs, if you have 2 similar computers, havign every thign same, and you enable HT on 1 system, and disable HT o otherm you'll find that the one with HT enables is opening documents faster than the one that has HT disabled.
got that?