kernel settings with x86 hyperthreading

[Fabio]

Hello,

I would like to know if hyperthreaded x86 computers need kernel SMP option 
activated in order to use that feature.

Furthermore, in the above-mentioned case, I need to know if FC3 is provided 
with a default SMP kernel because I have to install the distribution on a 
hyperthreaded P4 box and only after a while I will have time for kernel 
recompiling.

My last question is about the hyperthreading itself: Do we really get 
improvements by turning on that feature? The kernel has been written with 
supported multiple CPU operations, so I think it would benefit from hyper., 
but what about KDE, konqueror, kdevelop, qtdesigner and gcc (these are my 
most used applications) ?

I thank you all in advance for each reply.

Fabio