Power Consumption

With Vishera, AMD was in a difficult position: it had to drive performance up without blowing through its 125W TDP. As the Piledriver cores were designed to do just that, Vishera benefitted. Remember that Piledriver was predominantly built to take this new architecture into mobile. I went through the details of what makes Piledriver different from its predecessor (Bulldozer) but at as far as power consumption is concerned, AMD moved to a different type of flip-flop in Piledriver that increased complexity on the design/timing end but decreased active power considerably. Basically, it made more work for AMD but resulted in a more power efficient chip without moving to a dramatically different architecture or new process node.

In mobile, AMD used these power saving gains to put Piledriver in mobile APUs, a place where Bulldozer never went. We saw this with Trinity, and surprisingly enough it managed to outperform the previous Llano generation APUs while improving battery life. On desktops however, AMD used the power savings offered by Piledriver to drive clock speeds up, thus increasing performance, without increasing power consumption. Since peak power didn't go up, overall power efficiency actually improves with Vishera over Zambezi. The chart below illustrates total system power consumption while running both passes of the x264 HD (5.0.1) benchmark to illustrate my point:

In the first pass Vishera actually draws a little less power, but once we get to the heavier second encode pass the two curves are mostly indistinguishable (Vishera still drops below Zambezi regularly). Vishera uses its extra frequency and IPC tweaks to complete the task sooner, and drive down to idle power levels, thus saving energy overall. The picture doesn't look as good though if we toss Ivy Bridge into the mix. Intel's 77W Core i5 3570K is targeted by AMD as the FX-8350's natural competitor. The 8350 is priced lower and actually outperforms the 3570K in this test, but it draws significantly more power:

The platforms aren't entirely comparable, but Intel maintains a huge power advantage over AMD. With the move to 22nm, Intel dropped power consumption over an already more power efficient Sandy Bridge CPU at 32nm. While Intel drove power consumption lower, AMD kept it constant and drove performance higher. Even if we look at the FX-8320 and toss Sandy Bridge into the mix, the situation doesn't change dramatically:

Sandy Bridge obviously consumes more than Ivy Bridge, but the gap between a Vishera and any of the two Intel platforms is significant. As I mentioned earlier however, this particular test runs quicker on Vishera however the test would have to be much longer in order to really give AMD the overall efficiency advantage.

If we look at average power over the course of the two x264 encode passes, the results back up what we've seen above:

Power Consumption - Load (x264 HD 5.0.1)

As more client PCs move towards smaller form factors, power consumption may become just as important as the single threaded performance gap. For those building in large cases this shouldn't be a problem, but for small form factor systems you'll want to go Ivy Bridge.

Note that idle power consumption can be competitive, but will obviously vary depending on the motherboard used (the Crosshair Formula V is hardly the lowest power AM3+ board available):

Power Consumption - Idle

3D Gaming Performance Projected Performance: Can AMD Catch up with Intel?
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  • redwarrior - Thursday, October 25, 2012 - link

    You know NOT what you speak. Battlefield 3 is multithreaderd and look at AMD FX-8350 on Battlefield III - right up near the top, better than I 5 3570 and close to I7 3770. You guys are ignoring the facts and ignoring the trends in software. the move to parallelism is unstoppable and will accelerate. Multithreading is a growing presence and ONLY BAD programmers and software designers ignore it. The turning point will come when steamroller ships in a year and it will compete nicely with Hasbeen. At 28nm it will be almost as efficient as Hasbeen
    Performance wise it will be as good.
    Reply
  • CeriseCogburn - Tuesday, October 30, 2012 - link

    LOL why am i not surprised, massive amd fanboy with chips on the shoulder, and a fantasy brain.
    " o organizing work to liberate the working class from wage slavery"
    LOL - perfect, just like the rest of the amd fruitballs. Have fun at the OWS protests, though it would have been decent to join up with Tea Party, instead of coming on a year plus late after all the complaining. (you brought up politics fanboy)

    Anyway back to your fanboy fantasy. As I said, you can look all day long at the pileofcrap amd releases and tell yourself it's the greatest ball of cheese for you, but no one has to believe your bs. One big reason why.
    SB 2500K oc's to 4500 like butter on stock everything, all 4 cores, all day and all night with zero hiccups, and blows the amd crap away period.

    You actually have to be very stupid to not choose it. Very stupid.
    Be aware fanboy, you're looking at stock 2500K in all the charts, and a clear +50% increase in instantly available with it, FOR FREE.

    There is no way any amd fanboy made the correct decision after 2500K was released. And it's not occurring now either. You're living a lie, so please stop sharing it with us, and by the way - I don't think it's your place to tell others WHAT they can use their computer systems for.

    THEY OWN THEM, not you. They are theirs, not yours, and you shouldn't be tooting your virgin purity hippy love angel wing CRAP here, and then also have the obnoxious insolence to tell others they are wasting their computer power.

    There are plenty of people who will tell you flat out you are wasting your life and wrecking the nation with the crap you are doing, no doubt about it, so keep it to yourself, won't you ?

    Now let's hear how your crapdirver amd can possibly match a 2500K in the real world...
    LOL
    ain't happening mister

    Reply
  • Evilwake - Saturday, November 17, 2012 - link

    lol that funny calling a spade a spade look at yourself i my self have your 2500k and have the piledriver dont see any difference in them in the real world in fact whats funny is i can run many programs in the back ground and still play aion without any frame loose or any shuttering problems cant do that with my 2500k it drops in frame rates and shutters like hell so keep telling peeps how much u dont know about cpu's we really like hearing from u. Reply
  • CeriseCogburn - Sunday, December 09, 2012 - link

    another liar, another amd fanboy, another evil person Reply
  • iceman34572 - Wednesday, January 02, 2013 - link

    Who gives a crap who has the better processor? Honestly......do you work for Intel? Then why care what other people like? I have an FX series processor, as well as several Intel machines. I like them both. Going online and getting into a pi$$ing contest over which company makes a better processor and resorting to making fun of people (google "Internet tough guy and you'll see what a majority of people think about that) is non constructive, gains you nothing except negative attention, and makes you look less intelligent than you probably are. I could give a $hit what you like, or which processor you run. Neither AMD nor Intel pays me any money to give a d@mn, and whether I think you are wasting your money or spending it wisely doesn't impact me in the least bit. People, just buy what you personally like, and screw all the fanboyism that seems to be rampant ON BOTH SIDES. Reply
  • pmartin - Thursday, January 03, 2013 - link

    You hope it performs as well as Hasbeen. My guess is it won't. If you want top of the range performance, buy Intel, simple as that. Reply
  • pl1n1 - Saturday, October 27, 2012 - link

    The technical arguments have some merits, the political ones are per-digested socialist propaganda. I almost threw up at the end of the post.
    Must be nice to be able to advance the cause of the class struggle from a cozy living room somewhere in a free market country where your freedom of speech is protected by some freely elected capitalistic pig.

    Useful idiots from around the world unite!
    Reply
  • pmartin - Thursday, January 03, 2013 - link

    Please shut the hell up. Reply
  • captg - Wednesday, October 24, 2012 - link

    What about someone with an AMD Phenom II X4 940 Black Edition at stock speeds? Reply
  • Wisenos - Wednesday, October 24, 2012 - link

    i run my 965 @ 4ghz... 1.48v 20x200mhz Reply

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