Intel Pentium Extreme Edition 840 Processor Review
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Introduction and Dual Core Specifications
The race to dual core technology in a desktop platform has seemingly gotten more fierce than the race to the 1 GHz clock speed battle we saw years ago. AMD was the first to disclose the idea of their upcoming dual core technologies, and at this year's IDF conference, Intel disclosed their plans as well. While AMD seemed to have the lead as far as planning and technology went, Intel pushed up their release schedule quite a bit in order to be the first out of the gate.
Of course, the one in the lead at the beginning of the race isn't always the one winning at the end of the race, as any derby fan will tell you. So this the dual core debate will rage on for a while to come, with the first bout to occur here.
Intel's Pentium Extreme Edition 840 Dual Core
Intel's initial release of dual core processors comes in the form of this baby: the Intel Pentium Extreme Edition 840 processor. That's right, Intel has officially dropped the '4' nomenclature on their dual core parts.
The Pentium Extreme Edition 840 Processor
The processor package itself looks like any other LGA775 Pentium processor released by the chip giant, and that is a good thing -- common sockets and connectors usually indicate a much easier transition to a new technology. However, this doesn't mean that current users of LGA775 motherboards based on older chipsets are just going to be able to replace their current Pentium 4 with the new Pentium XE; a new chipset is going to be required in the form of the 955X, which we'll cover on the next page.
The same processor, only upside down
I'm going to briefly give an overview of the new technologies and specifications of the Pentium Extreme Edition processors here, but if you are looking for a more detailed explanation of everything Intel dual core, please look over my coverage of it in my IDF article.
A slide from the IDF presentation on dual core technologies gives us a quick overview on dual core technologies. Two (or more) independent execution cores on a single die defines the term "dual core" and the different die diagrams show the different ways that a dual core processor can be manufactured. The two options on the left show a dual core processor manufacturered on a single die, one with a two seperate cores and one with a two cores on a single logic piece. The third diagram shows a dual core processor with two two chips, one for each core. The third option would be the best one from a manufacturering point of view, because if a single core has a flaw, the entire processor doesn't need to be replaced, as is the case on the first two.
The Pentium Extreme Edition 840 that we are reviewing today is based on the first diagram, the Smithfield core.
Here are the quick specs on the new processor. The highlights include the indication of HyperThreading technology on the dual core processor and that translates into having a total of four threads possible on a single machine. Both cores run at 3.2 GHz and both have an exclusive 1MB L2 cache for a total of 2MB on the processor. The FSB is once again at 800 MHz, a decrement from the newest single core Extreme Edition Pentium 4 processors that ran on a 1066 MHz FSB. The latest technologies are included on the processor such as EM64T (64-bit extensions) and Execute Disable bit (security).
For those of you interested, the die size is around 206 mm^2, which is simply huge for a 90nm part and the transistor count is around 230 million! Below is a die shot of the Pentium XE 840
Pentium XE 840 Die
You can clearly see here that the Smithfield core processors are really just two Prescott cores fused together. This made the design of the processor easy to deal with, but limits some of the effectiveness of a dual core platform since both cores are sharing a single front-side bus. That means that any applications that were limited by a 800 MHz bus speed will see a small improvement (if any) going to dual cores as long as the FSB remains static.