Intel's Pentium Extreme Edition 955: 65nm, 4 threads and 376M transistors

Intel's move to their 65nm process has gone extremely well.  We've had 65nm Presler, Cedar Mill and Yonah samples for the past couple of months now and they have been just as good as final, shipping silicon.  Just a couple of months ago we previewed Intel's 65nm Pentium 4 and showcased their reduction in power consumption as well as took an early look at overclocking potential of the chips. 

Intel's 65nm Pentium 4s will be the last Pentium 4s to come out of Santa Clara and while we'd strongly suggest waiting to upgrade until we've seen what Conroe will bring us, there are those who can't wait another six months, and for those who are building or buying systems today, we need to find out if Intel's 65nm Pentium 4 processors are any more worthwhile than the rather disappointing chips that we had at 90nm. 

The move to 90nm for Intel was highly anticipated, but it could not have been any more disappointing from a performance standpoint.  In a since abandoned quest for higher clock speeds, Intel brought us Prescott at 90nm with its 31 stage pipeline - up from 20 stages in the previous generation Pentium 4s.  Through some extremely clever and effective engineering, Prescott actually wasn't any slower than its predecessors, despite the increase in pipeline stages.  What Prescott did leave us with, however, was a much higher power bill.  Deeply pipelined processors generally consume a lot more power, and Prescott did just that. 

Intel tried to minimize the negative effects of Prescott as much as possible through technologies like their Enhanced Intel SpeedStep (EIST).  However, at the end of the day, the fastest Athlon 64 consumed less power under full load than the slowest Prescott at idle.  Considering that most PCs actually spend the majority of their time idling, this was truly a letdown from Intel. 

With 65nm, the architecture of the chips won't change at all - in fact, the single-core 65nm Pentium 4s based on the Cedar Mill core will be identical to the current Pentium 4 600 series that we have today (with the inclusion of Intel's Virtualization Technology).  So with no architectural changes, the power consumption at 65nm should be lower than at 90nm.  As we found in our first article on Intel's 65nm chips, power consumption did indeed go down quite a bit; however, it's still not low enough to be better than AMD.  It will take Conroe before Intel can offer a desktop processor with lower power consumption than AMD's 90nm Athlon 64 line. 

In an odd move, just before the end of 2005, Intel is introducing their first 65nm processor.  Not the Cedar Mill based Pentium 4 and not even the Presler based Pentium D, but rather the Presler based Pentium Extreme Edition 955. 

The Presler core is Intel's dual-core 65nm successor to Smithfield, which as you will remember was Intel's first dual-core processor.  Presler does actually offer one architectural improvement over Smithfield and that is the use of a 2MB L2 cache per core, up from 1MB per core in Smithfield.  Other than that, Presler is pretty much a die-shrunk version of Smithfield. 

With 2MB cache on each core, the transistor count of Presler has gone up a bit.  While Smithfield weighed in at a whopping 230M transistors, Presler is now up to 376M.  The move to 65nm has actually made the chip smaller at 162 mm², down from 206 mm².  With a smaller die size, Presler is actually cheaper for Intel to make than Smithfield, despite having twice the cache.  Equally impressive is that Cedar Mill, the single core version, measures in at a meager 81 mm². 

The Extreme Edition incarnation of Presler brings back support for the 1066MHz FSB, which you may remember was lost with the original move to dual-core.  Given that both cores on the chip have to share the same bus, more FSB bandwidth will always help performance.

The Pentium Extreme Edition 955 runs at 3.46GHz (1066MHz FSB), thus giving it a clock speed advantage over all of Intel's other dual-core processors.  And as always, the EE chip offers Hyper Threading support on each of its two cores allowing the chip to handle a maximum of four threads at the same time.  Since it's an Extreme Edition chip, the 955 will be priced at $999.  If you're curious about the cheaper, non-Extreme versions of Presler, here is Intel's 65nm dual-core roadmap for 2006:

Intel Dual Core Desktop
CPU	Core	Clock	FSB	L2 Cache
???	Conroe	???	???	4MB
???	Conroe	???	???	2MB
950	Presler	3.4GHz	800MHz	2x2MB
940	Presler	3.2GHz	800MHz	2x2MB
930	Presler	3.0GHz	800MHz	2x2MB
920	Presler	2.8GHz	800MHz	2x2MB

As you can see, the Extreme Edition 955 will be the first, but definitely not the only dual-core 65nm processor out in the near future, so don't let the high price tag worry you. The remaining 900 series Pentium D chips should come with prices much closer to the equivalent 800 series.