Weekly Platform Trends: Prescott -- The Supercharged Pentium 4

After the Hyper-Threading 3.06GHz Pentium 4, what will Intel do for an encore? Well, in the short term, look for new chipsets and higher memory and bus speeds -- but this week, the chip giant tossed out a few tantalizing tidbits about its desktop flagship's 90-nanometer-process, 1MB-cache makeover. Can you say 'Pentium 5'?
Posted February 21, 2003

Vince Freeman

Intel Leads the Way To 90 Nanometers

Intel has a number of different strategies to blunt the blow of AMD's Hammer, and one of them was formally announced during this week's Intel Developer Forum -- the Pentium 4 successor codenamed "Prescott." Due in the second half of this year (most are betting on the fourth rather than third quarter), Prescott is all about smaller, faster, and enhanced technologies. While Intel doesn't want to stray too far from the highly successful Pentium 4 mix, the new core isn't your father's P4 by any means. In fact, Prescott may represent a more significant change than Intel's transition from the Pentium II to Pentium III processor.

The fundamental enhancement is Prescott's move from today's 0.13-micron to 0.09-micron (90-nanometer) process technology. This continual die shrinking (or, if not actually shrinking, at least packing more transistors into the same size chip) is one of the primary enablers of Moore's Law: As process technology becomes smaller, the CPU core requires lower voltages and can achieve higher clock speeds. According to Intel, nanotechnology isn't just for Michael Crichton thrillers -- the company touts Prescott's transistors as being smaller than the influenza virus, a charming thought.

The progression from 0.25-micron in 1997 to 90-nanometer manufacturing in 2003 -- and down to a target of 45 nanometers in 2007 -- is one of Intel's top priorities, and has allowed unprecedented growth in CPU speed while reducing chip voltages and unit costs. As a further refinement, Prescott is built with a strained silicon lattice that purportedly allows faster electron flow and hence higher performance; the slight increase in process costs is offset by Intel's trailblazing in carving chips from bigger, more cost-effective 300mm silicon wafers.

Bottom-line-wise, Prescott will debut at clock speeds north of 3GHz, with a projected ceiling of 5GHz or higher, all at a relatively low estimated core voltage of 1.2V. Yes, these are crazy numbers, but really no different than comparing the 1GHz Pentium III to the company's current 3.06GHz Pentium 4 monster.

It's a Bird, It's a Plane, It's Super Pentium 4

When you consider how different Prescott is from today's Pentium 4 core, it's no surprise that many expect it to arrive under a new name (so far, Intel's coyly calling the CPU merely the "next-generation processor based on NetBurst architecture"). Intel has rarely hesitated to rebrand existing technologies -- as in the case of the P-III and original Celeron, which were architecturally similar to the Pentium II -- and keeping the Pentium 4 moniker could seem a bit old school, especially with AMD gearing up to launch the Athlon 64 brand. The smart money would seem to be on Pentium 5, which retains the all-important Pentium brand yet upgrades it in the eyes of the consumer.

Technically, Prescott is unquestionably based on the Pentium 4 core, but there have been a number of improvements made, some a direct result of the smaller process technology. For example, while today's P4 "Northwood" features 8K of Level 1 and 512K of Level 2 cache, Prescott doubles the on-chip buffers to 16K and 1MB, respectively. The L2 cache upgrade is certainly important, but the boosting of the ultrafast L1 cache may actually be a more significant breakthrough. Intel was able to perform this upgrade due to its industry-leading advances in SRAM cell technology.

Intel has also tweaked the chip's overall architecture, with a faster data prefetch algorithm, improved Hyper-Threading capabilitie, and a revised die that lowers the clock skew -- yielding, Intel says, a fourfold improvement in clock distribution compared to Northwood -- and allows scaling to higher speeds. There are also 13 new x86 instructions, centered on improving multimedia and gaming performance. More surprising is the inclusion of Intel's "La Grande" hardware-based security technology, which certainly won't please many privacy or "fair use" advocates. Here's hoping it doesn't come with a Disney logo.

Can Intel Do No Wrong?

The chip giant is expected to move the Pentium 4 to the new "Springdale" i865 chipset and an 800MHz front-side bus early this spring, so Prescott should make a seamless entry into the installed platform base. Intel certainly has the corporate market in tow, but this is also great news for upgrade aficionados, and could establish Intel as the front-runner for enthusiast dollars -- remember, AMD is moving to totally divergent socket and platform designs for the Athlon 64 and Opteron processors, a fact that hasn't gone over well with some market sectors.

Intel also surprised us by formally certifying DDR400 memory as a supported technology, which is another smart move given the current DDR climate and Springdale's dual-channel memory controller and DDR bus. Whether full DDR400 support makes it way into the mainstream Springdale (or high-end i875 "Canterwood") chipset is still uncertain, but supplied documentation mentions select modules that do qualify. This difference may seem slight, but many motherboard chipsets have the theoretical ability to run DDR400, yet make you sort through a boxful of modules before finding one that's stable and compatible. On the other hand, chipsets like Nvidia's nForce2 allow full use of 400MHz memory. Only time will tell which path Prescott takes.

At its core, Prescott is a processor technology the market can sink its teeth into. Smaller, faster, cooler, and better are all words that resonate with the end user, and Intel is certainly not deviating from a game plan that works. The 533MHz-bus Pentium 4 is already blazing fast, and it'll be most interesting to see what this superchip does when given an 800MHz bus and dual-channel DDR400. That should be a show unto itself.

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