Just like Microsoft roadmaps, you learn to take Intel roadmaps with a pinch of salt. That's why it comes as no surprise that the release of the 4GHz version of the Pentium 4 has been delayed for at least one quarter.
"The high-speed chip was scheduled for release this fall or by the end of the year. Intel on Thursday informed computer manufacturers that the processor is now set for the first quarter of 2005." - eWeek.
Such delays are, as stated, far from uncommon. The next generation Centrino mobile platform (Sonoma) was already pushed back earlier this month. It seems that a number of Intel releases scheduled for this year may well now be coming in 2005 instead.