Intel's Dual Core Strategy Investigated
by Anand Lal Shimpi on October 22, 2004 3:09 PM EST- Posted in
- CPUs
Been hearing conflicting dual core information lately? Here's a compilation of everything we have and know about Intel's dual core plans for the next two years.
Dual Core for Desktops in 2005
Intel has yet to determine what brand they will market their first desktop chips under, although we'd expect them to continue to use the Pentium 4 brand but with some sort of appendage like Extreme Edition or Lots of Cores Version. Intel has, however, already determined what the specifications and the model numbers of their dual core chips will be.
Currently set for release in Q3 2005, Intel has three dual core chips on their desktop roadmap: the x20, x30 and x40. The only difference between these three chips is clock speed, with the x20 running at 2.8GHz, the x30 running at 3GHz and the x40 running at 3.2GHz. All of the chips are LGA-775 compatible and run off of an 800MHz FSB. Hyper-Threading is not enabled with Intel's dual core chips.
As far as architecture goes, the x-series of dual core CPUs from Intel are built on the little talked-about Smithfield core. While many have speculated that Smithfield may be Banias or Dothan based, it's now clear that Smithfield is little more than two 90nm Prescott cores built on the same die. There is a requirement for a very small amount of arbitration logic that will balance bus transactions between the two CPUs, but for the most part Smithfield is basically two Prescotts.
But doesn't Prescott run too hot already? How could Intel possibly build their first dual core chip out of the 90nm beast that is Prescott? The issue with Prescott hitting higher clock speeds ends up being thermal density - too many transistors, generating too much heat, in too small of a space. Intel's automated layout tools do help reduce this burden a bit, but what's important is that the thermal density of Smithfield is no worse than Prescott. If you take two Prescotts and place them side by side, the areas of the die with the greatest thermal density will still be the same, there will simply be twice as many of them. So overall power consumption will obviously be increased by a factor of two and there will be much more heat dissipated, but the thermal density of Smithfield will remain the same as Prescott.
In order to deal with the fact that Smithfield needs to be able to run with conventional cooling, Intel dropped the clock speed of Smithfield down to the 2.8 - 3.2GHz range, from the fastest 3.8GHz Prescott that will be out at the time. The reducing in clock speed will make sure that temperatures and power consumption is more reasonable for Smithfield.
Smithfield will also feature EM64T (Intel's version of AMD's x86-64 extensions), EIST (Enhanced Intel SpeedStep Technology) and Intel's XD bit support. Chipset support for Smithfield will come from Glenwood and Lakeport, both of which support the 1066MHz FSB (as well as 800) and Dual Channel DDR-2 667 and 533. Glenwood (the successor to 925X) will support up to 8GB of memory, making it the perfect candidate for EM64T enabled processors that want to break the 4GB barrier.
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HardwareD00d - Friday, October 22, 2004 - link
#16, The reason hyperthreading will be disabled with dual cores is because WindowsXP only support 2 processors right now. I'm not sure about Windows 2000, but Intel has said you should not enable HT with that OS.I heard that Intel is hoping that M$ makes a "patch" to XP so it will do 4 processors. AFAIK, Intel is waiting on that for the "official word" on HT in dual core.
thelanx - Friday, October 22, 2004 - link
So these are underclocked 3.8 prescotts? That could be prove to be a great overclock with water cooling maybe, as it'll be virtually garuanteed 3.8 GHz or more, just gotta make sure you've got adequate cooling.thelanx - Friday, October 22, 2004 - link
GhandiInstinct - Friday, October 22, 2004 - link
So for now it's just an advanced version of hyper-threading, instead of virtual cpus you have physical cpus, thanks Anand.sprockkets - Friday, October 22, 2004 - link
How are the 2 cpus connected with Intel? Why disable hyper-threading for having extra cores, oh well, guess it makes some sense. What then we could do is make 2 cores with a split amount of ALUs and FPUs.Jeff7181 - Friday, October 22, 2004 - link
#13... Water cooling won't be a necessity. Don't forget, with the increase in heat from dual cores there's also an increase in surface area for that heat to be dissipated through. I don't think you'll see a huge increase in CPU temperature at all. What WILL increase more is power requirements, and case temperate... as well as the temperature of the room the PC is in and probably the size of the heatsink.xsilver - Friday, October 22, 2004 - link
Anand, how did you measure power consumption from your last batch of reviews? hardware or software? links? thanksRegarding dual cores, aren't these cpu's going to be horrendously expensive to produce if they are basically 2x prescotts?-- and if there is 200w power consumption, isn't that mandatory water cooling territory?
Anand Lal Shimpi - Friday, October 22, 2004 - link
Jeff7181True, but I was mostly referring to 800MHz FSB chips, the 533MHz parts will still be available then too.
supertyler
You pretty much answered your own question there, monitoring user inputs are generally not CPU intensive tasks at all - in fact you could say that those tasks are mostly user limited :) A huge benefit to dual core (or SMP in general) is that if you have one renegade application that eats up a ton of CPU power, you still have a separate CPU that can continue to work for you during the interim. It is a tangible performance improvement, but one of few for desktop uses.
Marsumane
It's tough to say what's going on with AMD until we actually see more roadmaps. For now, they haven't increased clock speed all that much either, remember we're still at 2.6GHz at a maximum with the fastest non-FX Athlon 64 running at 2.4GHz. As far as building more fabs goes, they cost about $2.5B a piece and take quite a bit of time to build, I don't think that's exactly the quickest fix to the situation at hand :)
skunkbuster
Remember that Banias and Dothan are designed with clock speed limitations in mind, they need smaller manufacturing processes to actually reach higher clock speeds as they natively have very short ramping abilities. For more information take a look at my Banias or Dothan reviews.
GhandiInstinct
In a single threaded application, no they will not be any faster. In a game for example, two 3.2GHz cores will not be faster than a single 3.2GHz core.
Take care,
Anand
klah - Friday, October 22, 2004 - link
These will still be using 1.385V? If so, 200W+ power consumption?GhandiInstinct - Friday, October 22, 2004 - link
"The vast majority of applications on the desktop are still single threaded, thus garnering no real performance benefit from moving to dual core"Anand,
So two 3.2ghz cores will not be faster than one 3.2ghz core?