The speedstep module is present in 2.4.20-2.2 , but somehow it disappeared from
2.4.20-2.10 (it's missing both from the i686 package and from the kernel-source
one). The latest 2.4.20-2.15 still does not have it.
Still missing in Phoebe-2 and still missing in kernel-2.4.20-2.25 in rawhide.
It came back around 2.36 or so.