I've just posted a complete review on the Pentium 4 2GHz and the new Intel D850MD & D845HV motherboard that respectively feature the i850 & i845 chipsets. I've passed recent Intel platforms under the grill comparing the Pentium 4 1.7/2.0GHz to a Celeron 1.2GHz and Pentium III 1.13/1.2GHz. And as you'll see the results are surprising, especially for the Celeron CPU. Be sure to check the exhaustive benchmarks page to know what to expect from Intel processors. Below is a snippet from the review:

Intel has recently unleashed the fastest processor in terms of frequency on the market. A couple of months after the Gigahertz barrier has been broken the Santa Clara based CPU Giant established a new record and doubled the speed with the release of the Pentium 4 2.0 GHz. This new processor is available in two different flavors: 423 and 478 pin packages. The most interesting model is obviously the 478 pin one. Still engraved in 0.18�, and despite the fact it comes with more pins than previous Pentium 4 CPUs it is much, much smaller. Intel engineers have worked hard to miniaturize their most powerful processor so it can take less space on motherboards. The Pentium 4 family is the first of Intel CPUs to feature a newly designed architecture since the Pentium Pro was released in 1995. In the past weeks, Intel has demonstrated a strong wish to popularize its Pentium 4 platform: even if the Pentium 4 2.0GHz isn�t a model of affordability for the masses, slower processors like the 1.8 or 1.9GHz have suffered severe price drops that are always welcome by customers. As Bill Gates sees at least one PC in every household, Intel would like to see one Pentium 4 based computer in every family. The Pentium 4 2 GHz sets the bar higher for Intel�s competitors and paves the way for the upcoming Northwood CPU generation. Intel actually clearly leads the MHz war with a processor running 600MHz faster than its first direct competitor. However MHz isn�t always synonymous with performance. This review is one of the most complete to date, with benchmarks comparing the performance of almost every Intel platform from the Celeron, to the Tualatin 1.2 GHz and the Pentium 4 2 GHz using i845 or i850 based motherboards.