on my P4 its HT Hyper Transport i think... what exactly is that, on my dual core it has the pc usage thing on taskmanger split in 2 for 2 cores... but so does my P4
Okay first of all, HT stands for Hyper-threading, not Hypertransport. Hypertransport is a technology used by AMD 64 chips. Basically your computer see's two cpus when there is only one. It helps you multitask, and do a lot of things at once.
For P4, it's Hyperthreading, and it creates a virtual core so you see two instead of one. This allows tasks to be split up and it allows both the real and virtual core to work.