Power Consumption: Athlon 64 vs. Athlon 64 X2

In Part II of our preview of Intel's dual core processors, we noted that the addition of a second CPU core generally didn't increase overall system power consumption by that much. In fact, the Pentium D 2.8GHz vs. single core 2.8GHz comparison yielded only a 15% increase in system power consumption under load for the dual core CPU. While we didn't look at power consumption in our dual core Opteron review, armed with desktop parts, we were ready to look at how desktop power consumption was affected by the move to dual core.

Single core AMD CPUs have always consumed less power than single core Intel chips; in fact, the 130nm Athlon 64 FX-55 consumes less power than a 3.0GHz Pentium 4 (5xx or 6xx series).

How much more power would a dual core Athlon 64 X2 consume? To answer this question, we looked at three CPUs on the same platform and measured system power consumption. We used a 130nm Athlon 64, a 90nm Athlon 64 and a 90nm dual core Athlon 64 X2 - all clocked at the same frequency and with the same per-core cache sizes. The results are below:

AMD Single Core vs. Dual Core Power Consumption

At idle, the Athlon 64 X2 falls directly between the 90nm Athlon 64 and the 130nm Athlon 64, but does the same hold true when the system is fully loaded performing our WMV HD encode test?

AMD Single Core vs. Dual Core Power Consumption

Surprisingly enough, it is. Clock for clock, the Athlon 64 X2 will consume less power than a 130nm Athlon 64, and less than 20% more power than a 90nm Athlon 64. Note that the Athlon 64 X2 4200+ compared here also consumes less power than all single core 90nm Intel Pentium 4 CPUs. Even the Athlon 64 X2 4800+ consumes less power than all single core 90nm Pentium 4 CPUs.

If you're worried about the Athlon 64 X2 generating too much heat, there's no reason to be concerned - if you're happy with the heat levels of your current 130nm Athlon 64, the X2 will run even cooler.

Index Business/General Use Performance
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  • PetNorth - Tuesday, May 10, 2005 - link

    #88 (not 48 lol)

    "Pd (3.2) vs X2 (4200+), Pentium D wins price/ performance"

    What are you talking about?

    PD 3.2 estimated cost is $530 and X2 4200+ estimated cost is $537. Not to mention much more expensive board and DDRII. And X2 4200+ simply smokes to PD 3.2 in basically everything.


  • classy - Tuesday, May 10, 2005 - link

    Was it possible to drop the multiplier to 11 so we could see the potential performance of a 4400+?
  • PetNorth - Tuesday, May 10, 2005 - link

    #48

    "Pd (3.2) vs X2 (4200+), Pentium D wins price/ performance"

    What are you talking about?

    PD 3.2 estimated cost is $530 and X2 4200+ estimated cost is $537. Not to mention much more expensive board and DDRII. And X2 4200+ simply smokes to PD 3.2 in basically everything.
  • wharris1 - Tuesday, May 10, 2005 - link

    Sorry about my original post inquiring about NCQ; I failed to notice the PATA notation on the Seagate. Having said that, would you consider comparing the multitasking performance with NCQ enabled and disabled on these new dual core X2s?
  • CrimsonChaos - Tuesday, May 10, 2005 - link

    Nice review. I'm in the crowd of those who can't wait for (AMD) dual-core processors to become available. As far as I can tell, the X2 4800 ran games nearly as fast as the FX-55 and outperformed the FX-55 in multi-tasking. So what reason is there to buy the FX-55 once these are released (assuming prices are close)?

    #84 - I do not think that the background tasks of Anti-Virus and Anti-Spyware programs use much CPU. Aside from the initial launching of the program, the CPU usage to keep the program running is minimal -- if any at all. I was under the impression they just ate up RAM while running. Correct me if I'm wrong?

  • psyched - Tuesday, May 10, 2005 - link

    Anand, was this tested on 32bit version of XP? Wouldn't the #s be even more in favor of X2 should we have the proper drivers and run it under XP x64 OS?

    Psyched.
  • DigitalDivine - Tuesday, May 10, 2005 - link

    Pricing for the X2 dual cores within amd product like makes sense. 4200+ is a tad faster than the 4000+ only in mutlitasking mode, but then that's why you are buying dual cores anyway, for multitasking multithreading.

    but once you put intel's pricing in the mix, with intel's capacity to just churn out silicon, they can afford to price these much lower. unlike amd, pricing it down to stimulate demand...

    the x2's sit in the happy middle of the Pd, and the PEE, and the pricing shows that.

    Pd (3.2) vs X2 (4200+), Pentium D wins price/ performance

    but X2 (4200+) vs PEE (3.2), X2 wins hands down. which is kinda sad, the 4800+ is not even challenged.

    300 vs 500 vs 1000, those are the competing prices for the chips... so it's a bit hairy to compare.

    now, dual core 256k or even 128k would be welcomed, as we saw performance betwen sempron 3100+ and the a64 2800+, performace with half the cache is negligable. so if amd makes dual cores with 256k cache or even 128k, that could help with the transistor count and keep the total area small. giving amd some slack in cost, and lower power consumptions. (*but that doesn't necessarily mean lower prices to consumers).

    * i can only hope and dream
  • Jeff7181 - Tuesday, May 10, 2005 - link

    #85... with dueling cores Unreal 3 will suck... the processors will be too busy dueling with eachother to run the game. ;)
  • jkostans - Monday, May 9, 2005 - link

    Awesome article. I was reading an article over on tom's hardware on the X2 where they did a little more intensive power consumption test. Here is a quote which really got my interest,

    "However, there is something that we can't really tolerate: the Pentium D system manages to burn over 200 watts as soon as it's turned on, even when it isn't doing anything. It even exceeds 310 W when working and 350+ W with the graphics card employed! AMD proves that this is not necessary at all: a range of 125 to 190 Watts is much more acceptable (235 counting the graphics card). And that is without Cool & Quiet even enabled."

    I just felt this is something anandtech didn't touch on as thoroughly and should really be considered. I mean a 350w PS will fry or shut down using one of these bad boys in a gaming machine. I wouldn't even feel safe with my Vantec 400w PS.
  • stance - Monday, May 9, 2005 - link

    Anand, Please write article showing what future
    games will be like with duel core cpu's and
    if with bois updates performance might increase.

    future game i.e. UNREAL III

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