The contenders
We'll be comparing the new Pentium 4 to its top x86 competitors, pictured below, plus the top contenders from the x86 value market, the 900MHz Intel Celeron and 1GHz AMD Duron.

Pentium III 1.2GHz, Pentium 4 (Socket 423), Pentium 4 (Socket 478), Athlon We should point out that while the microPGA Pentium 4's packaging is quite a bit smaller than the rest of the field, the chip itself, inside all of the packaging, is the largest of the bunch (though the same size as the Socket 423 P4 chip). Still, the miniature packaging is pretty spiffy.

Making sense of the megahertz "myth"
One of the things we have to return to again and again when evaluating the latest processors is the question of clock speed—usually measured in megahertz and gigahertz—and how that important variable affects overall performance. Now that we've hit the symbolic 2GHz milestone, it's appropriate to stop and consider the question in more depth. We've had quite a bit of confusion about clock speed of late, in part thanks to the Pentium 4's penchant for especially high clock frequencies. We've also had a Mac-versus-PC flare-up that led to some stern words over Apple's somewhat deceptive attempts to make an otherwise-important point. (Apple hand-picked six Photoshop filters on which to base a comparison, then called the 866MHz G4 "58% faster" than a 1.7GHz Pentium 4.)

How MHz has mattered
Whatever you think about Apple's marketing, the truth remains that clock speed isn't everything. It is possible for a 1.2GHz processor to outrun (or completely crush) a 2GHz processor in real-world performance. Many things help determine a system's overall performance, and the P4's tendency to run at stratospheric clock speeds creates a substantial marketing problem the for likes of Apple and, more directly, AMD. The PC market—and especially its sales and marketing arms—has keyed in on clock speeds for years as an indicator of overall performance. Not only performance, in fact: it's safe to say that MHz has equated to merit. A 900MHz system is widely recognized by consumers as "better" than a 700MHz system.

That perception is a bit naive, but its foundation is solid. Generally, clock speed has served as a marker for a PC's place in the grand scheme of things. Before you scoff, consider that in an Intel-dominated PC market, MHz is a surprisingly effective marker. It can tell you all sorts of things about a PC in an instant. For instance, say you have two retail desktop PC systems, one 333MHz and the other 350MHz. Judging by the clock speeds, they're probably Pentium IIs. One system has a 66MHz front-side bus (FSB), while the other has a 100MHz FSB. The 333MHz box talks to memory at 66MHz, while the 350MHz box uses PC100 SDRAM.

Then compare that 350MHz box to a 1.2GHz system. We're probably looking at AGP 2X versus 4X, ATA/33 versus ATA/100, a system without USB ports versus one with four, the list goes on—a wide disparity in hard drive performance, graphics chip horsepower, RAM, and more. The standard amount of RAM on the 350MHz box probably matches the amount of RAM on the 1.2GHz box's graphics card.

This sort of feature escalation is standard practice for the Dells and Gateways of the world, and it's one reason why the "MHz myth," as it's been called, has been an effective means of communicating a very complex reality to consumers, whether those consumers be clueless first-time PC buyers, aloof IT managers, or even in-the-know PC enthusiasts. (I hate to do it, but I feel bound to note that in the case of the G4, 866MHz is a pretty good marker. The Mac system probably has a 133MHz FSB, PC133 memory, and an ATA/66 storage interface, much like an older, 866MHz Pentium III system. Not that that's the whole story.)

Needless to say, if you're selling an Athlon-based PC that runs at 1.4GHz and your competitor is selling a 2GHz Pentium 4-based system for a similar price, you're going to be fighting a nasty uphill battle—even if your product actually offers more bang for the buck. If you have to count on the wannabe-geeks in blue knit shirts at Best Buy to explain "the megahertz myth" to consumers, you are in deep, deep trouble.