Is this possible? I didnt think so:
HyperThreading was already present on the very first Northwood, it just wasn't enabled.
It's only enabled on the P4B 3.06 & all the P4Cs & cannot be enabled on previous P4s.
Why did they do such a thing?
There's a lot of things which defy reason. If you discover the answer, you will be shot.
They added HT when they did the transition from 0.18 to 0.13. Intel always adds loads of functions but doesn't enabled them out of the box.
When there is a market that can actually use these extra features, or shall we say a market that's willing to pay more to use those features, they activate them.
Prescott CPUs allready have the x86-64 compatible instructions. Intel is just waiting to see if the market is really moving towards x86-64 before enabling them.
Wow... wow wow wow.. man, its like they are keeping us back