Report: Apple severely underclocks MacBook Pro GPU to save power, lower heat

“Apple appears to have underclocked the ATI Radeon Mobility X1600 graphics chip in its MacBook Pro laptop. According to one online report, the GPU’s core runs 35 per cent slower than the clock speed recommended by ATI. The memory clock is 41 per cent below par,” Tony Smith reports for The Register. “The speed differential was spotted by a poster on French-language site MacBidouille, the site reports. The correspondent ran ATI’s ATI Tools utility – version 0.25, a beta release – running under Windows XP. The software revealed his MacBook Pro’s X1600 was clocked at 310MHz and the memory at 278MHz (556MHz effective).”

“Apple’s motivation would seem to be to keep the MacBook Pro’s overall thermal envelope down in order to keep the fan running as slowly as possible and the system as quiet as it can make it. There’s a battery life benefit too,” Smith reports. “According to the forum poster, who followed up his initially finding by installing “ATI-optimised drivers” rather than the ones supplied by Apple, his Counter Strike benchmark test with all settings pushed to the max and the resolution set to 1,440 x 900 saw frame rates jump from 61 to 97. Of course, that’s under Windows XP – it remains to be seen how Mac OS X users can gain the same benefit.”

More in the full article here.

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  1. i just picked this up off of another forum, let’s stay objective folks. I’m not attesting to it’s accuracy, but open minds are better than FUD.

    “Also, keep in mind that the graphics chip in both the iMac and Macbook Pro are underclocked to 400/400 GPU/RAM and 300/300 GPU/RAM respectively, though judging by these numbers, the Macbook Pro clocks it up to 400/400 once it gets a graphics-heavy application running”

  2. ” You’re doing the same as those Liberals who try to make the aswers fit their arguement even if it’s an answer from another questions.”

    That was relevent to the topic. I supposed I should be glad that anyone is buying mac hardware but since Steve and I are such good democrats who supported Dean and give heavily to the democratic party, hardcore conservatives in the apple camp seems strange to me.

    Don’t hate on linux guys. I love Apple and OS X but they aren’t perfect for everyone and there’s no guarantee Apple will kick ass for ever. Since windows is all but unusable to me I like to know that there’s an option number three. Having more choices for decent OSes is a good thing.

    And shame on apple for not letting the consumer make this decision. The macbook pros probably perform just fine as is but if there’s a way to squeeze more power out of them I think we should be allowed to. Allow the user to select profiles for the GPU and warn them that it’s more likely to over heat if it’s set to the max. These things probably have 5 thermometers that prevent it from frying itself already.

  3. “You’re doing the same as those Liberals who try to make the aswers fit their arguement even if it’s an answer from another questions.”

    careful cowboy… more than one forum brawl has statred over less

  4. Being a mobile graphics chip, doesn’t it lower the clock rate when not being used, like the Core Duo processor to increase battery life? So when they measured the clock frequency of the GPU, were they actually taxing it with any 3D graphics at the time?

    All I know is when I play heavy 3D games on my MacBook Pro, that’s when I hear the CPU and GPU fan spin up to help keep them cool. If Apple was downclocking the GPU, then how exactly did they get such great reviews running Windows from all the PC mags out there?

    Ignorance is bliss I suppose…

  5. No, the Mobility ATI 1600 doesn’t reduce its clock speed to reduce power. It has other tricks up its sleeve, such as shutting down unused circuitry when not in use and reducing bandwidth to the PCI-E bus, but that’s it. The clock speeds should remain constant. Indeed, you can see that this must be true by the original article – when the author threw out Apple’s driver and used a standard Windows driver he got the full clock speed and much better performance. Underclocking when not in use would not explain the huge frame rate differences seen with the Apple driver when running a 3D intensive game.

    Let’s be clear here. Apple market the GPU on the Macbook Pro as a key feature of this laptop. Go look at the marketing on their web page. They use gaming framerates as a benchmark. No where do they point out that they have dramatically reduced the speed of a what is otherwise a quite respectable graphics card. ATI recommend its operation at 470MHz – Apple are running it at 300MHz. I’m astonished by some of you on this forum who find this defensible. Really. WOuld you defend Microsoft if they pulled a similar trick?

    For what it’s worth it seems that Apple have underclocked the GPU in the new iMac as well. See These users have managed to install a MacOS overclocking utility to put the speed back at the correct value and are seeing significant performance improvements.

  6. Lets look at the glass half full instead of half empty.
    If the MacBook Pro is as fast as everyone says it is, then
    lets see the potential it has, especially considering the greater percentage of users will never tax or max out the graphics processor anyways. If you want multiple firewire and USB ports on a mobile machine, then buy a hub at Walmart. Hey, to look at it positive, maybe there is less ports to incorporate an additional tiny little fan across the graphics processor in the upcoming Macbooks next week.
    As for Vista, just think of all the creative ideas your mind could have inside it if it weren’t so cluttered with all your constant and never ending worries about viruses, spyware, malware, botched defragmentation, blue screen of death, etc. And for your claim to Linux, nothing really substantial to run on it except for server stuff. You have alot of free time going to the Mac sites, when you are supposed to be using your time writing checks to Symantec, Norton, and Micro$oft for your protection. You are getting slack, troll, and are dropping the ball. Oh, I’m sorry, you never had the ball to begin with.

  7. So, to be clear then Georgy Porgy, your argment is that it doesn’t matter if Apple cripple their hardware because there’ll always be some users that don’t need the speed, you can always buy some 3rd party add-ons anyway, and hey, Windows is crappier anyway so stop complaining.

    You’re a genius. You should work for Apple’s marketing department.

  8. Okay, let me get this straight. The WINDOWS driver supplied by Apple for the PUBLIC BETA of BootCamp runs the GPU at a lower clock speed.

    And this allows us to conclude…. what???

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