Athlon, Core 2 architectural efficiencies compared

If you go shopping for sub-$100 processors right now, you’ll be faced with two main contenders: Core 2-based Intel chips and AMD Athlon X2s. The Athlons typically have higher clock speeds for the price, but their Intel rivals often perform better. Why?

A good two years after the debut of the Core 2 Duo, Real World Technologies has put together an in-depth comparison of the Athlon and Core 2 designs. Rather than delve into the obscure architectural details of the two offerings, RWT used apps called VTune and CodeAnalyst to poke around under the hood and get hard numbers for things like instructions per clock, branch predictor accuracy, and how the chips handle their L1 and L2 caches.

The results are quite interesting. Kanter compared a 2.8GHz Athlon 64 FX-62 with a 2.93GHz Core 2 Extreme X6800 in four games, and he found that the Core 2 split instructions into more μops than the Athlon, and—unsurprisingly—processed a greater number of instructions per clock (around 5-10% more). Branch prediction tests showed “vastly” greater accuracy on the Intel front, with “about 50% fewer mispredicted branches per instruction retired.” Kanter does nonetheless point out that branch-prediction accuracy was comfortably above 90% for both chips. Finally, on the cache front, Kanter found that AMD had a more effective L1 cache, while Intel’s L2 cache had “about 50% fewer misses per instruction retired.”

That said, we should note that Kanter compares a 90nm dual-core Athlon with a first-gen Core 2 Duo. Things might look a bit different in new Phenoms, 65nm Athlons, and 45nm Penryn CPUs (like the 2.5GHz Pentium E5200), and they’ll probably change even more once we start comparing Intel’s Core i7 processors with AMD’s 45nm Phenoms.

Comments closed
    • moritzgedig
    • 11 years ago

    speculative execution and branch-prediction have such an impact!
    not only on the execution but also on the powerdraw.
    as AMD is unable to do it as good as intel. They should find a way around it.
    hyperthreading and more not so speculative cores should be looked into.
    now that the singlecore performance has reached it’s limit (until there is some major tech change) the code will have to be parallel anyways, thus one can change to another thread, instead of using resources on chance.
    likely the number of cores per CPU will double every 3 years, that would be 8 cores in every PC in 2014. Until then, programmers will have to have found, a way of easyly making multithreaded code.
    It can’t be that hard, humanity has achived harder things befor.

    • crabjokeman
    • 11 years ago

    Real World Tech,
    2006 called. It wants its review back.

      • dkanter
      • 11 years ago

      Well when 2006 called, I asked if we could get the economy back – but they told me I should start with this article ; )

      Actually, I’m a little embarrassed at how long it took to do this, but it’s one of those things that takes a lot of effort and we had to restart dozens of times.

      I hope you found it interesting though.

      David

        • DrDillyBar
        • 11 years ago

        cool. When’s Part 2? 🙂

    • Vaughn
    • 11 years ago

    it shouldn’t feel like a dinosaur, im still running a Opteron 170 tho with 4GB of ram just upgraded from 2GB. Vista runs great on my rig and I haven’t really found anything that is forcing me to upgrade yet.

    • Homerr
    • 11 years ago

    I use an E8400 system at work and have an E6850 at home. I had to work on an older s939 4200+ X2 system yesterday and was pleasantly surprised that it didn’t feel like a dinosaur.

    • sdack
    • 11 years ago

    This is not exactly news, is it?

    • A_Pickle
    • 11 years ago

    g[

    • ybf
    • 11 years ago

    CPU + game = inadequate use of resources.

    I keep my nVidia 8800 GT warm running the CUDA version of the Folding At Home client, and use the other 95% of my Yorkfield cycles on a stack of BOINC grid projects.

    Interestingly, I can do this 24/7, and have found only one application that has any problem running at “normal” interaction rates while all this is going on in the background, and its only problem is initial startup (it wants me to pause BOINC or it takes 5 minutes instead of 5 seconds; probably a stupid choice of default task priority buried in some component of the .NET library the slow app is based on).

    Microsoft may have screwed up a lot of fiddly things in Vista, but the scheduler was not one of them. I’d love to spend 8 months inside Redmond pushing the knobs until it’s got a true real-time mode…

    Oh, and it runs Allied Assault: Airborne at full screen-res and full fidelity with zero visible inadequacies, but for that I kill the charityware.

    • Hattig
    • 11 years ago

    Good article. Will be interesting to see how Phenom compares to the older K8 core design as used however.

    • DancinJack
    • 11 years ago

    l[

    • tfp
    • 11 years ago

    It’s nice that people still write in depth articles. I always enjoy reading Real World Techs write-ups.

      • DrDillyBar
      • 11 years ago

      Me too. Great articles at RWT.

    • StuG
    • 11 years ago

    I know alot of people have always said the X2 architecture as less efficent than a C2D, but i’m glad to see someone just break it down into simliar terms. I still <3 my X2, put that thing through hell and it still is running great after many years of my stupid abuse.

      • BoBzeBuilder
      • 11 years ago

      How do you abuse a chip? They are designed to process information.

        • UberGerbil
        • 11 years ago

        Overclocking? Overvolting? Running in a badly-ventilated enclosure with an inadequate heat sink?

          • StuG
          • 11 years ago

          Ventalation Problems? No. Everything else? Yes. I would have though that chip would’ve burned out on my quite some time ago. I have it running at stock speeds again in my back up system, but in all fairness it shouldn’t probably be alive XD

            • BobTheBacterium
            • 11 years ago

            Plus, there are those times he comes home late, drunk, and feels that his X2 simply deserves it

            • Tamale
            • 11 years ago

            HAHA

            • StuG
            • 11 years ago

            trust me bob..many…many nights.

    • mbowen89
    • 11 years ago

    What would YOU get? The new Core i7 or a Phenom?

    Core i7 for me!

      • Peldor
      • 11 years ago

      With my money? Core2.

      With your money? Corvette.

      • StuG
      • 11 years ago

      Idk, my Phenom does great in games for me, and it was easy to make alot fo my old stuff work. Now the i7 needs better ram, entire new mobo, and from rumors it doesn’t perform in games (which is what I use my main comp for). So only time will tell, but I intend to probably stick with my Phenom for a very long time.

        • accord1999
        • 11 years ago

        /[< Now the i7 needs better ram, entire new mobo, and from rumors it doesn't perform in games <]/ Only versus Yorkfield Core 2 Quads, which when paired with a 4870X2 is a far better gaming platform than Phenom with the same video card.

        • UberGerbil
        • 11 years ago

        The i7 performs in games. The rumors are saying it doesn’t perform /[

          • moshpit
          • 11 years ago

          Good advice!

          • mbowen89
          • 11 years ago

          So you would say that my best bet is to keep my E8400 OC to ~4GHz, and upgrade my 8800GTS 512 to something like the HD4870X2?

          I have 4GBs of RAM, XP Pro…I wonder if I should get Windows 7 with that 4870X2?

          😀

            • d0g_p00p
            • 11 years ago

            Yep, target video card. I have a E8400 running at stock because my CPU is not the bottleneck in games. I have even pushed my E8400 to 4+Ghz on air and I got about 6+ FPS more. However moving from a 8800GTS 320 to a 4870 I saw a HUGE FPS increase.

            • mbowen89
            • 11 years ago

            Ok, my next upgrade will be an HD4850/70.

            But right now, I think I am going to order a Western Digital VelociRaptor 150GB this week.

            Anyone else agree on this? 😀

            I can’t wait!

            ——–

            Edit: Man this is ripping me apart. I only have a P5k-e, which doesn’t even have PCI Express 2.0 x16…and my 8800GTS 512MB is still pulling its wait.

            Ehh, I am just a poor college student, I don’t need to stay on the top! 😀

      • ew
      • 11 years ago

      Considering an entry level Core i7 system will probably be more expensive then a system with the best Phenom it is hard to answer that question.

        • OneArmedScissor
        • 11 years ago

        I’d take a 45nm Phenom, because really, even current Phenoms are enough, and those will be quite a bit better, but AFFORDABLE, unlike putting together a Core i7 based PC.

        As it is, I’d say Phenoms are largely proportional in price to performance with Core 2s, excluding maybe the 125w 9950 vs. the Q6600, since the price went up on the first and down on the other. Of course, that wasn’t the case back when they ran up to $240 or so, but they’ve come down quite a bit, and the Core 2s haven’t, and won’t, for likely a year.

        Even if the 45nm Phenoms don’t match Core 2s EXACTLY, it will be VERY close, but they’ll undoubtedly be cheaper.

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