The Intangible Dual Core

The move to dual core is a bit of a "catch 22". In order to deal with the fact that a dual core die is twice the size of a single core die, AMD and Intel have to use higher yielding transistors.  The larger your die, the more defects you have; so, you use higher yielding transistors to balance things out.  The problem is that the highest yielding transistors run at the lowest clock speeds, so dual core chips end up running at slower speeds than single core chips.  While the Pentium 4 could have hit 4GHz last year, we won't break the 4GHz barrier until late 2006 at the earliest. 

In Intel's case, we're talking about 2.8GHz - 3.0GHz vs. 3.6GHz - 3.8GHz for the high end single core chips.  In order to offset the difference, Intel is pricing their dual core chips within about $80 of their single core counterparts.  Short of giving dual and single core chips a price parity, this is by far the best approach to assuring dual core adoption. 

Why does Intel want to encourage dual core adoption?  To guarantee a large installed user base, of course.  The problem today is that the vast majority of desktop systems are single processor systems, meaning that most developers code applications for single processor systems.  To encourage a mass migration to develop multithreaded applications, the installed user base has to be there to justify spending the added time and resources in developing such applications.  As we just finished mentioning, Intel's approach is the quickest way to ensure that the exodus takes place.

So, with dual core CPUs priced very close to their single core counterparts, the choice is simple right? 

On the Intel side of things, you're basically giving up 200MHz to have a dual core processor at virtually the same price.  But things get a lot more complicated when you bring AMD into the situation.  AMD hasn't officially released their dual core availability and pricing strategy, but let's just say that given AMD's manufacturing capacity, their dual core offerings won't be as price competitive as Intel's.  Now, the decision is no longer that simple; you can either get a lower clocked dual core CPU, or a higher clocked single core AMD CPU for the same price - which one would you choose? 

The vast majority of desktop application benchmarks will show the single core AMD CPU as a better buy than the dual core Intel CPU.  Why?  Because the vast majority of desktop applications are single threaded and thus, will gain no benefit from running on a dual core processor. 

Generally speaking, the following types of applications are multi-threaded:

  • Video Encoding
  • 3D Rendering
  • Photo/Video Editing
  • most types of "professional" workstation applications

However, the vast majority of other applications are single threaded (or offer no performance gain from dual core processors):

  • office suites
  • web browsers
  • email clients
  • media players
  • games, etc.

If you spend any of your time working with the first group of applications, then generally speaking, you'll want to go with the dual core CPU.  For the rest of you, a faster single core CPU will be the better individual performance pick.

But once again, things get more complicated.  Individually, single threaded applications will make no use of a CPU able to execute multiple threads.  But, run more than one of these applications at the same time and all of the sudden, you're potentially dispatching multiple threads to your processor and thus, potentially, have a need for a multi-core CPU.

The Platform: Intel 955X Scheduling and Responsiveness
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  • Hans Maulwurf - Monday, April 4, 2005 - link

    #27 thats because these benches are opted for HT and dual core. Everybody should know they are not typical for usage of a desctop PC.
    Maybe dual core will be a good thing, but to value its implementation you have to compare it to, for example, a dual Xeon.

    If I would take this review seriously we all should have buyed dual CPU systems some time ago. But some time ago nobody could show dual CPU desctop systems are useful.

    Why did this change so radicially? Is it really the way we use our computers or is it just the way you benchmark when allowed to be one of only very few Intel-previewers?
  • Son of a N00b - Monday, April 4, 2005 - link

    #11, next time label you post with *Caution Fanboy Post* so I do not waste my time reading your comments that are biased and misinformed...

    w0w! great preview, I cannot wait until six months from now you doing a head to head match up with SLI, dual core cpu rigs from both AMD and Intel....it should be very interesting indeed....Cannot wait to see what AMD's performancee is...it could go either way....

    Anyway great article, keep up the great work that keeps us all coming back, it must be hell to come up with new benchmarks for these systems.

    w00t go anandtech and dualies!
  • MaxisOne - Monday, April 4, 2005 - link

    Hey Not even 1 Game Benchmark ? and wheres the temps ??
  • MaxisOne - Monday, April 4, 2005 - link

  • cbuchach - Monday, April 4, 2005 - link

    I think these are the first benchmarks I have seen where Hyperthreading was shown to make a significant performance difference outside of video encoding tasks or a few other specialized apps.

    Overall I think Hyperthreading amongst the enthusiast community has never held much worth mostly because it has little impact on gaming performance. But these benchmarks clearly show in my eyes that whether it be the single-core/hyperthreading or dual core chips, Intel is the way to go. I of course am not a big gamer but nonetheless most computer users, especially power users at least do some moderate multitasking. Having two virtual or real cores really does improve the computing experience up unitl this point, in mostly immeasurable ways.
  • redpriest_ - Monday, April 4, 2005 - link

    When can I buy one? =P

    These previews will probably be followed up by shipping versions 6 months from now.
  • AtaStrumf - Monday, April 4, 2005 - link

    WAU this was a shocker! Sure didn't expect dual cores so soon.

    Great preview Anand! It covered all of the areas I was interested in and it basicly confirmed all my expectations.

    It seems that one thing that can still bring dual cores to a grind is the I/O bottleneck. With everything going dual lately and with RAID controllers being as common as USB ports and HDDs being pretty cheap, I think it's time you retested how much of an impact RAID can have on desktop performance. If I remember correctly it was you who said that RAID made no sense on desktop, which essentially killed my burning desire to get one. What about now? If we're going dual we might as well go all out.
  • tynopik - Monday, April 4, 2005 - link

    try running stuff with software raid5 eating up cpu cycles
  • Beenthere - Monday, April 4, 2005 - link

    Hyperthreading does NOT significantly improve system performance unless the software is written for hyperthreading and there is damned little of that currently available. Dual core when execurted properly offers a considerable performance advantage. Intel's cobbled mess is sure to be a nightmare and when all the facts are known it will be impossible to conclude otherwise despite the cheerleading of the media.
  • sri2000 - Monday, April 4, 2005 - link

    #14 - As you say the enterprise market is where multi-processor rigs live (whether dual-cpu or dual-core), it's also where dual-core makes it's best financial case.

    ie. when Microsoft came out to say that their software license pricing will treat a dual-core cpu as a single processor (as opposed to pricing it as a dual-proc), that really gives businesses (especially small ones with tight budgets) a great incentive for getting dual-core servers (not to mention for those who're using Linux).

    And since AMP will get dual-core Opterons out ahead of dual-core Xeons, it's an opportunity to get some nice growth in their small business server market share.

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