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Intel's Pentium Extreme Edition 840 processor


Dual dual core core action action!
— 3:09 AM on May 5, 2005

ABOUT ONE YEAR AGO, Intel went public with the first news of its near-religious conversion to the gospel of multicore processors. Prior to that fateful day, Intel had been talking optimistically about hitting 4GHz clock speeds by the end of 2004 and eventually reaching 10GHz with the Pentium 4 "Netburst" architecture. Such achievements were, in fact, business as usual at the world's largest chipmaker before news of its conversion. But everything changed last May when the company ripped up its roadmaps and started over again, deemphasizing clock speed as a measure of performance and reworking its CPU development efforts top to bottom to favor multiple processor cores per chip.

The move was a radical conversion and a stunning act of agility from a company so large and so invested in long-range planning. Judging by the results, however, it seems to have worked. The Pentium Extreme Edition 840 has arrived roughly one year after news broke of Intel's big shift in direction, the first fruits of the new era of parallelism.

Pentium who?
The first thing you may notice about the Pentium Extreme Edition 840 is the name, which conspicuously does not include the words "Pentium" and "4" arranged together back to back. Intel has revamped its naming scheme for its dual-core chips, despite the fact that the Extreme Edition 840 packs a thoroughly Pentium 4 heritage.

In fact, this dual-core chip, code-named "Smithfield," is actually a pair of Pentium 4 "Prescott" cores situated together on a single piece of silicon. Each core has 1MB of L2 cache onboard, and the two cores share an 800MHz front-side bus. Beyond the Siamese twins action, there's very little to differentiate these chips from the latest Pentium 4 processors like the 600 series. Like those chips, Smithfield features support for Intel's EM64T extensions for 64-bit computing, and it can save on power consumption via the one-two punch of an enhanced halt state and SpeedStep power management.


The Extreme Edition 840 looks just like any other LGA775 chip

Smithfield is also manufactured using the same basic 90nm fabrication process as current Pentium 4 chips. However, it's roughly twice the size of the Prescott core at 230 million transistors and 206 mm2 of die space. Heck, have a look at a picture of the Smithfield die, and you'll know instantly what's up.


Double vision?

I swear I did not make this up in a paint program. Smithfield really is two Prescott cores side by side.

For starters, Intel will be selling four versions of Smithfield, and the version we're reviewing today is the highest end product. The Extreme Edition 840 is clocked at 3.2GHz and has Intel's Hyper-Threading technology enabled. If you pay the premium for the Extreme Edition, you get the extra coolness factor of seeing four CPU utilization graphs charted in Task Manager or your CPU monitor of choice. The more pedestrian versions of Smithfield will be dubbed the Pentium D, and they will not include Hyper-Threading support. Here's how the whole product line shapes up:

CPU Clock speed Hyper-Threading? Price
Pentium D 820 2.8GHz No $241
Pentium D 830 3.0GHz No $316
Pentium D 840 3.2GHz No $530
Pentium Extreme Edition 840 3.2GHz Yes $999

Prices will range from $999 for the Extreme Edition 840 to as low as $241 for the Pentium D 820, although pricing on the Pentium D processors isn't yet 100% official. Obviously, with these kinds of prices, Intel is dead serious about pushing deep into the desktop PC market with dual-core products right away.

I am a little perplexed about the choice of Hyper-Threading as a means of setting apart the Extreme Edition from the regular Pentium D. Yes, I understand that Intel needs something to make its flagship processor special, but Hyper-Threading offers decent performance gains, sometimes of up to 50%, through thread-level parallelism precisely at a time when Intel is pushing the industry heavily in that direction. Disabling Hyper-Threading for the vast majority of Smithfield-based chips out there, which will be Pentium D processors, seems like a drastic measure. We've generally accepted Hyper-Threading as a Good Thing on the Pentium 4 and would hate to see it go.

With this concern in mind, I asked Intel whether there wasn't some ulterior motive involved in this choice beyond product segmentation. To my surprise, their answer was no. Apparently, this capability will lie dormant in most of the world's Smithfield-based processors in order to keep the Extreme Edition looking, er, extreme.