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AMD FX: Energy Efficiency Compared To Eight Other CPUs

Bulldozer: Improvements Are Urgently Needed

Our article AMD Bulldozer Review: FX-8150 Gets Tested thoroughly explores the technical details of AMD's general architecture and the products that emerge from it. It sheds light on the design, performance per core, power management, second-gen Turbo Core, and potential improvements in Windows 8, which is aware of AMD's architecture and can optimize for it.

However, the conclusion is crystal clear: there are very few arguments in favor of the FX CPU right now. Performance improvements above and beyond the Phenom II X6 are limited to heavily-threaded applications. In case of modern applications that don't utilize multiple threads, this Bulldozer digs its own grave. The only way to properly utilize the FX processor is to run applications able to tax its eight integer cores.

But today’s topic is energy efficiency, measured in performance per watt of consumed electricity. This is where AMD had a real chance to shine, given its move from 45 nm manufacturing to 32 nm lithography. The company also made significant improvements to the way its architecture cut power use, employing power and clock gating to minimize waste. Energy could have been saved and, assuming performance comparable to last generation's hardware, efficiency would still get a nice boost. 

Our own suite of tests includes a number of single- and multi-threaded applications, all updated to the latest versions possible. Run as scripted suited, they give us a general picture of efficiency that doesn't frame AMD's FX processors in a very positive light. In spite of a higher clock rate and more cores, the effective performance per clock cycle is, as we all know, lower. A higher frequency does not translate into substantial efficiency gains, even in the face of a more advanced 32 nm process node. Performance is adequate only when multi-threaded applications are run. As such, AMD is treading water with respect to efficiency, and we certainly wouldn't fault the AMD fans who continue buying Phenom II processors as a way to save some money.

On the desktop, efficiency probably isn't as important as it is in the enterprise space, where racks full of servers quickly multiply any weaknesses in power use. The FX doesn't seem to run any hotter than AMD's existing processors, and its performance is more or less ample even for power users. If you are, in fact, in the market for a platform upgrade, consider waiting to see what Intel's Ivy Bridge design will do. After all, FX would require you to buy a new Socket AM3+-equipped motherboard anyway. Ivy Bridge will see Intel introduce its 22 nm manufacturing process, hopefully dropping power use even as the company increases performance.

In order for AMD to compete with that architecture, its forthcoming Piledriver design needs to incorporate significant improvements to IPC and power. Incidentally, the company claims that both are set to receive some attention. Until then, we'd hope to see AMD dropping the prices on FX to get us interested.

  • compton
    The low idle and load power consumption numbers of the SB K series are why I love them so much. Less power = less heat and noise, and SB is certainly worth it for me. BD, on the other hand, is just a strange bird. Someone out there could probably find a way to leverage it successfully, and that one person is going to be very happy. Maybe Bulldozer makes a lot more sense in its server configurations -- but I really wish AMD had just given the Phenom II a slight dust-off and die shrink. Everyone was pulling for AMD to do something great with BD, and the efficiency results are just abysmal. If you got great performance, but dis-proportionally high power consumption, that would be okay as well. With BD, you get the worst of both world, and not much of a saving grace. Perhaps Trinity will do something with this albatross that is BD and make it respectable, because the efficiency comparison is embarrasing.
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  • de5_Roy
    thank you tom's. this kind of article (performance-efficiency analysis) is one of my favorites. i've been waiting eagerly for an article like this from reviewer sites, tom's beat everyone else. :D
    the benchmarks with real world softwares(and not some specialized highly threaded synthetic benchmark that gives biased results) are the ones that matter to me. i use some of the softwares occassionally (blender), some more frequently (winrar, 7zip, lame encoder) and this article helped me a lot when i choose my next pc.
    did you guys see the ridiculous tdp number on cpu-z screenshot of fx8150? 223 w what the !@#$. i wonder which one got it wrong, amd or cpu-z.
    amd-fans-in-denial can argue as much as they want, but the reality didn't change. the efficiency numbers pretty much mirrored the bd review - bd isnt power efficient. even the ph ii 980 - the most power hungry of phenoms is more power efficient than fx 8150. and people who don't care about power consumption should care about the cooling and maintenance bd would need along with a power hungry high performance gfx card. imagine running an air-cooled fx 8150 @ 4.7 ghz with nvidia gtx 580 or radeon hd 6990.
    i can use any kind of acronyms like 'lol' or 'lmao' on bd's laughable power efficiency(even lynnfield beat it!) and performance but i am really sad and disappointed.
    if amd can't compete with intel, intel will keep selling their cpu at a high(and higher) price - avg users like me will be the loser.
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  • tacoslave
    everytime i read a BD article i die a little inside. Plus what we all knew would happen already started Intel already raised the K series prices a couple bucks.
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  • compton
    Geez, the 2700K is creeping up on $400. Thanks a lot AMD. You're off my Christmas list.
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  • dragonsqrrl
    comptonGeez, the 2700K is creeping up on $400. Thanks a lot AMD. You're off my Christmas list.Ya, the MSRP is $332, but the price on newegg is $370. Even for a brand new processor that's a huge premium over MSRP. It'll stabilize to the $330 price range eventually, but this initial price hike is no doubt related to the Bulldozer launch.
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  • de5_Roy
    @compton: phenom might get a die shrink with the llano upgrade. according to the latest trinity leak, llano's new 'husky' core will feature a phenom ii class cpu with amd 6xxx class gpu. this is just a rumor though.
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  • soccerdocks
    Thank you very much for including Matlab in the benchmarks. Its a really informative benchmark for those in engineering.
    Reply
  • "Everyone was pulling for AMD to do something great with BD, and the efficiency results are just abysmal."

    Not really, for the most time everyone was aware that BD was not going to be a SB killer, AMD themselves had hinted at it, then their PR department (propaganda office I would say) started pumping up the hype.

    Reply
  • amk-aka-Phantom
    And this is exactly why AMD fanboys should STFU about Bulldozer being an "excellent server CPU". You don't want high power consumption on a server.
    Reply
  • amk-aka-Phantom
    dragonsqrrlYa, the MSRP is $332, but the price on newegg is $370. Even for a brand new processor that's a huge premium over MSRP. It'll stabilize to the $330 price range eventually, but this initial price hike is no doubt related to the Bulldozer launch.
    2700K is BS... 100MHz extra is definitely not worth it. 2600K and 2500K remain best bang for buck right now.
    Reply