Headroom is, essentially, the amount of additional clock speed a version of a processor can be enhanced with after its introduction, due to manufacturing refinements. Intel's current-generation Pentium III chip, according to convention, should have an additional 200MHz left in it. Pentium III Coppermine chip could, in theory, go at least as high as 1,200MHz. 1,200MHz and faster Likely speeds for the future gigahertz-plus Pentium III, based on Intel's 133MHz bus, are 1,066MHz, 1,133MHz and 1,200MHz, with 1,266MHz being the next possible speed. I don't think that they've decided yet where to go.
Market demand is another factor.
But the main factor may be the competitive landscape . AMD in May is expected to launch the next-generation of its Athlon processor, the main rival to Intel's Pentium line. Willamette's claim to fame, Intel said, will be performance. The company demonstrated the chip running at 1.5GHz last February. Although an enhanced Pentium III could conceivably match megahertz with Willamette, Intel could avoid competing with itself by pricing Pentiums lower and claiming greater levels of performance for Willamette, McCarron said.