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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  • Quanticles - Monday, May 9, 2005 - link

    #63

    you going to hire anand as a consultant? lol
  • Viditor - Monday, May 9, 2005 - link

    Anand...thanks muchly for the reply!
    I guess I just wanted to know if you had compared memory timings (I should have known that you had!).

    I'm just trying to get a handle on what will perform well and under what circumstances (I don't know if you noticed above, but I just had a colleague put a hold on a $90,000AUD order because of many of todays reviews...your input really DOES matter!).
    While rendering speeds are the paramount issue for me, multitasking is also important.
  • Jeff7181 - Monday, May 9, 2005 - link

    Overclock it! :D
  • Viditor - Monday, May 9, 2005 - link

    Nat, thanks for the reply.

    "for some reason the high end P4's have *felt* like faster desktop processors to me"

    I hear what you're saying...to me, they don't seem faster but they do seem "smoother". It feels sort of like the AMD's drive in a lower gear but with higher RPMs, you may be going the same or faster speed but the ride's a lot "torquier" (is that a word?) so you both accelerate AND decelerate faster.
  • GentleStream - Monday, May 9, 2005 - link

    OK, I'll be patient.
  • bob661 - Monday, May 9, 2005 - link

    #51
    Synthetic benchmarks do not generally correlate to real world applications. There's no bias, you're just a dumbass.
  • Anand Lal Shimpi - Monday, May 9, 2005 - link

    GentleStream

    I'm still working on additional multitasking tests (including a skype/gaming test as well as the multitasking compile test) but they didn't make it into this review.

    Take care,
    Anand
  • GentleStream - Monday, May 9, 2005 - link

    So where is the multitasked compile test? You did the compile test in the last review for building Firefox but did not do a parallel compile i.e.
    such as make -j 4. That is the test which I was really looking for.
  • fitten - Monday, May 9, 2005 - link

    #46 Actually, no. I use (and write) multithreaded and multiprocess code every day for a living as well as for fun. I can't wait for the X2s to come out so I can buy one (I've been planning on it for over a year now!). I've already got everything picked out, I just need the dang things to be available!

    Btw, I'm also a gamer of sorts so I have to pay attention to both the programmer and the gamer inside me :P
  • Anand Lal Shimpi - Monday, May 9, 2005 - link

    "but that possibility is always there."

    I've always been very clear that this is *not* how things work at AnandTech. I specifically delegated all advertising duties to a separate company to ensure that there wasn't even a chance for manufacturers to have any influence on any AnandTech editors. From a business standpoint, you can run a much more successful business if your loyalties lay with your readers and their desires rather than with manufacturers. Credibility is everything and we'd have to be pretty stupid to sacrifice that for any amount of money or manufacturer favoritism. A lot of things in life just boil down to common sense, and how we work at AnandTech is one of them.

    Take care,
    Anand

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