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?


View All Comments

  • 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!
  • 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
  • Origin64 - Wednesday, October 24, 2012 - link

    4.8GHz? My Phenom II doesnt even do 4, but I have an extremely shitty mobo. vdrops like a downer after a suger rush. Reply
  • BSMonitor - Tuesday, October 23, 2012 - link

    Except that it requires nearly double the power of a Ivy Bridge to squeak out a few wins in those multi-threaded apps... Only when a company is this close to obscurity can we say this is a win. Especially in light of ARM competition with x86... AMD continues with insanely power hungry chips?? Not good.

    At $200 it still is a tough sell. Double the power of i5-3570K and 80W more than i7-3770K. No way. The chip looks dated. cough cough Pentium 4 Prescott anyone?

    What market is AMD aiming at here?!? Intel produces 2 IVB per 1 of these. And IVB is an APU of all things.. This thing is AMD's non-iGPU part. Imagine if Intel released an 6-8 core IVB without the iGPU. Same die size as the IVB APU.

    Bleak does not even begin to describe AMD. The fact that AMD sits at $1.5B market cap and no one is talking about buying the company says a lot.
  • CeriseCogburn - Tuesday, October 30, 2012 - link

    Thank you for the proficient monitoring, although I disagree with at least the characterization of calling it a win based upon amd being on it's way out, or whatever.

    It gets called and referred to as a win, because honesty is now CRAP, and fanboy fruittard is "in". That's all.

    When there is some bare win for amd in some game, then of course it's a massive killing and total destruction, and sometimes when it's a tie or a lose it gets called and manipulated and talking pointed and spun into a win.

    Personally, I believe that's why amd is a freaking failure. They coddled and produced a large raging fanboy base, with their PR hits against nVidia and Intel, all of it lies that the fruiters totally believed, and went on a continuous rampage with.
    That emotional battery allowed AMD to produce crap, not support their crap properly, feel good about their little warm and "not evil" hearts they pretended to "live by", and thus go down the frikkin tubes while bathing themselves in glory.

    The very few times the massive collective of lockstep fanboy parrots broke out of their idiot mind chains and actually criticized AMD, and it only occurred several times mind you, after much ignoring and glossing over, why then AMD, shocked and stunned - WOKE THE HECK UP... got off their coddled PR fanboy based BUTTS - and did something about their huge problem...

    I must say the results those few times were extraordinary for AMD, and quite exemplary in any overall comparison across the board to other companies in the mix. A few examples of that should not be hard to bring to mind.

    That's why I don't like the fanboy crap. I certainly don't believe it's good for amd, nor good for my bottom line, as I suffer under the constant coddling and lying, too.
    We all do.

    Now it's likely too late, but I'm still hoping for a bailout for amd. Lots of oil sheiks out there.
  • Yoda's apprentice - Wednesday, June 26, 2013 - link

    It kind of bothers me how you ignore that you're exactly the same fanboy too. Reply
  • Wolfpup - Tuesday, October 23, 2012 - link

    Yeah! I'm really impressed how much better these are...the fact that they're beating Intel again in ANYTHING is awesome!

    We need AMD for the competition, and anymore with Intel pushing their worthless video so hard, it gives AMD a competitive advantage both because they can skip video and have more transistors on CPU, OR they can put in a massively better GPU.

    I wish they had an 8 core notebook part though for the mid range with no integrated GPU....it seems like that ought to be a solid enough choice for a system, combined with a high end Nvidia or AMD GPU.

    Seriously thinking of making my next notebook AMD, both to support them, and to avoid switchable graphics... (well, still have AMD's switchable graphics, but hopefully since they make the whole thing they'll do better).

    I used to be scared off by AMD as I got burnt twice on horrible 3rd party chipsets, but I bought a c50 based notebook last year for the kitchen, and it's been 100% rock solid stable and non-weird...like Intel's always been known for. Makes me feel a lot better about buying an A series notebook this year or an FX desktop.
  • Beenthere - Tuesday, October 23, 2012 - link

    FYI - Anandtech is suffering server issues at the time of this post...

    What many reviewers and fanbois tend to miss over and over is that AMD is delivering the best performance-for-the dollar and that ANY current model desktop CPU will run ANY software just fine. Unless you have some enterprise level software that brings a modern CPU to it's knees, ANY of the currently avialable desktop CPUs will run Windoze or Linux based software just fine. In fact Linux apps do even better in many cases than Windoze bloatware.

    I have no idea if AMD will ever offer a discrete CPU to equal Intel's top of the line, over-priced models nor do I care. I buy what delivers the best performance for the price. I have yet to purchase any AMD desktop CPU that would not run ALL software as well as an Intel CPU, without any isses what so ever.

    If all you do is benchmark all day long and you have money to burn, blow it on an Intel CPU, unless of course you are opposed to evil, chronic, law violating corporations looking to eliminate consumer choice. You could always vote your conscience, if you have one.

    I am always amazed that people actually falsely believe that AMD processors are some how "inadequate". Even with tainted benches, AMD processors deliver all the performance and good value that most consumers desire. It's tough however getting people to look at the data objectively. All most people think of is that "more" is better, when in fact that's the sucker play when you look at performance vs. cost and actual needs.

    Considering that Intel got a whopping ~5% performance gain from a 32nm to 22nm node drop and Tri-gate tansistors with Ivy Bridge, (along with over-heating and poor overclocability...), AMD did quite well to deliver a ~10-15% improvement with Vishera. With AMD's pricing Vishera should sell well because of it's excellent performance and cost.

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