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Tom's CPU Architecture Shootout: 16 CPUs, One Core Each, And 3 GHz

Tom's CPU Architecture Shootout: 16 CPUs, One Core Each, And 3 GHz
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The CPU landscape is really complex. Both AMD and Intel offer tons of different models. But how would today’s processors perform if they didn't have multiple cores? We take 16 different CPUs and compare them all using a single core running at 3 GHz.

Ever since AMD and Intel started cramming more processing cores into their CPUs, potential performance has grown faster than it did back when single-core CPUs were king thanks to parallelization. Back then, pushing higher frequencies and improving performance per clock were the only ways to speed things up. Now, a developer has to optimize his application to take advantage of multiple cores. But doing so enables scaling that simply wasn't possible before.

We all know that more advanced manufacturing technologies are paving the way for more cores per CPU, and that clock rates are slowly creeping up as well. But how have AMD and Intel improved the performance each core is capable of delivering at a given frequency? Are today’s CPUs any faster than a five-year-old Core 2 if you compare a single core at the same speed? We grabbed 16 different processors from both companies and ran our latest benchmark suite with each operating at 3 GHz. This story examines how they all do in what most folks would consider a very experimental shootout between artificially-created single-core CPUs introduced in the past five years.

Prerequisites and Processors

In preparation for this article, we had to look at the processors available to us for benchmarking. Of course, we wanted to include AMD’s and Intel’s latest products sporting four and six cores. We also thought it'd be important to include a larger number of dual-core products. After all, much has changed since the Athlon 64 X2 and Pentium 4 ruled the jungle. Our selection includes first- and second-generation Core processors with two, four, and six cores, plus Phenom II, Athlon II, and Athlon 64 X2 models.

It's really a challenge to find motherboards for a job like this if you really want to limit core usage in the BIOS. We had to try a lot of potential subjects before finding one for each CPU interface that'd let us modify the number of active cores. And since we couldn't be sure that disabling processing cores in the BIOS would physically turn them off, we refrained from measuring power consumption.

The 3 GHz Battle

This comparison wouldn't have made much sense if we ran each processor at its default clock rate. In addition to limiting the number of active cores to one, we also locked down the frequency of each chip to 3 GHz. We also switched off all power-saving mechanisms like Cool'n'Quiet and SpeedStep, as well as performance-enhancers like Turbo Core and Turbo Boost. As a result, we can be sure that the conditions for testing each CPU are identical. There are only two exceptions. Our Clarkdale- and Lynnfield-based chips run at 2.93 GHz. We could have hit 3 GHz by tweaking base clocks and multipliers, but that would have altered the results. Losing 66 MHz is measurable, sure, but it shouldn't alter the bigger picture.

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  • 31 Hide
    Darkerson , July 26, 2011 5:43 AM
    This was a pretty nifty article. Hope you guys revisit it after Bulldozer and Ivy Bridge drop. Thanks!
  • 22 Hide
    jcesmi , July 26, 2011 8:05 AM
    Where are those bots i buy all my cloths from?
  • 21 Hide
    fstrthnu , July 26, 2011 5:51 AM
    Thing is, Intel will already have their updated Sandy Bridge processors by the time Bulldozer comes out - which will probably maintain the gap. AMD would need a MASSIVE effort to catch up or even pass Intel at this point. Bulldozer's going to have to try really hard to win back the high-end enthusiast market. Intel clearly has had much better direction from Intel Core up to now.
Other Comments
  • 31 Hide
    Darkerson , July 26, 2011 5:43 AM
    This was a pretty nifty article. Hope you guys revisit it after Bulldozer and Ivy Bridge drop. Thanks!
  • 2 Hide
    fstrthnu , July 26, 2011 5:45 AM
    Wow, this has got to be one of your biggest comparos EVER. Didn't finish reading it yet, but it looks like this one will be quite a doozy
  • 4 Hide
    wintermint , July 26, 2011 5:47 AM
    Well AMD hasn't released a new architecture in a long time.. what you expect?
  • 21 Hide
    fstrthnu , July 26, 2011 5:51 AM
    Thing is, Intel will already have their updated Sandy Bridge processors by the time Bulldozer comes out - which will probably maintain the gap. AMD would need a MASSIVE effort to catch up or even pass Intel at this point. Bulldozer's going to have to try really hard to win back the high-end enthusiast market. Intel clearly has had much better direction from Intel Core up to now.
  • 11 Hide
    dragonsqrrl , July 26, 2011 5:55 AM
    Every single comment posted before Darkerson (there were quite a few) seem to have mysteriously vanished... strange.
  • 8 Hide
    cangelini , July 26, 2011 6:12 AM
    dragonsqrrlEvery single comment posted before Darkerson (there were quite a few) seem to have mysteriously vanished... strange.


    How many more were there? That's not something I've seen happen before.

    Best,
    Chris
  • 5 Hide
    Lewis57 , July 26, 2011 6:14 AM
    One of the most interesting articles I've seen from toms. I already had an idea of the standings between intel and AMD per core per clock by how game minimum specs usually say something like "Minimum Intel Core 2 Duo 1.8Ghz or AMD Athlon x2 2.4Ghz", but it was nice seeing it put into perspective.

    Hope you revist it with bulldozer/ivy bridge.
  • 2 Hide
    crisan_tiberiu , July 26, 2011 6:18 AM
    Great review, long live my i7 2600k :) 
  • 4 Hide
    yyk71200 , July 26, 2011 6:39 AM
    Looks like Bulldozer is going to combat SB by moderate increasing of IPC AND increase in frequencies. Purely by IPC it will lose to SB but if it can deliver high frequencies at the same time, we may have a decent competition.
  • 1 Hide
    dragonsqrrl , July 26, 2011 6:44 AM
    cangeliniHow many more were there? That's not something I've seen happen before.Best,Chris

    I don't know for certain, maybe around 6 or 8. I'm only aware of this because I was one of the people who posted a comment.
  • 4 Hide
    Anonymous , July 26, 2011 6:48 AM
    Now this was a great article! Good work guys!
  • 9 Hide
    yyk71200 , July 26, 2011 7:00 AM
    DjEaZy... you couldn't wait until the bulldozer comes out?

    I think it may be a bit difficult to test bulldozer this way because configuration of cores within modules is rather funky. That is they are not full fledged cores within a module.
  • 14 Hide
    clonazepam , July 26, 2011 7:25 AM
    Pretty cool article.

    Thanks.

    That must have been one tedious sob to pull off. I wouldn't have had the discipline to even finish the P4 tests lol...

    I'm gonna go stroke my kentsfield... I think it knows when the new system's up, it's going to be subjected to 1.5+ volts ala Frankenstein's Monster... bwuahahahaha
  • 4 Hide
    PreferLinux , July 26, 2011 7:44 AM
    yyk71200Also, clock for clock testing is not always fair. For example, in P4 vs. Athlon 64 days clock for clock testing would not be fair because while P4 was much worse in IPC, it was designed for higher frequencies. Sure, Athlon still bit it in most cases, but gap was much narrower that clock for clock tests would suggest. We may have a similar situation (in reverse) in SB vs. Bulldozer.

    You talking stock or overclocked? And if overclocked, then is it a 24/7 clock with what cooler? My point is that we don't really have any idea how Bulldozer will compare in clock speeds – it could be very well at stock but very poorly when overclocked (24/7 clock, but once again I'm not specifying with what cooling (could be low-end air to high end water or even LN2!) – but same on each), for all we know.
  • 22 Hide
    jcesmi , July 26, 2011 8:05 AM
    Where are those bots i buy all my cloths from?
  • 9 Hide
    outlw6669 , July 26, 2011 8:09 AM
    Excellent work reviewers!
    It is great to see a solid, in depth, tech article again =D

    @yyk7120, the entire point of this article was to show the relative IPC performance between the different architectures.
    In a battle of pure IPC performance, nominalizing all variables is not being unfair, it is entirely necessary.
    Think of it more as an in depth look into the underlying architectures rather than another AMD vs Intel @ price point that most are so used to.
  • 14 Hide
    memadmax , July 26, 2011 8:16 AM
    This is about as close as you can get to real raw core efficiency. I love this article and was wondering the same thing as well.
  • 20 Hide
    Anonymous , July 26, 2011 8:25 AM
    I would LOVE to see one additional page - 'performance per transistor'

    Basically - take the performance data, and divide the results by the amount of transistors per core (eg 1 billion transistors for 8 core -> 125 mil transistors for core). There would be a bias towards CPUs with huge L3 cache (as they can use all of it), but it would still be very interesting thing to see

    I would really want to see how the efficiency of the processors increased compared to the amount of transistors they use
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