Apple Mods Intel Chipset for Auto GPU Switching

When Apple announced that its new 15- and 17-inch MacBook Pros had both the Intel HD IGP as well as a discrete Nvidia GT 330M GPU and it could switch seamlessly between them automatically, we assumed that it was using the Nvidia Optimus technology – but it isn't. Instead, Apple brewed up its own software solution, which works in a slightly different fashion, Ars Technica reports.

While Nvidia Optimus uses a software-driven list of apps that would trigger a system to switch over to discrete graphics, Apple's solution detects on the OS level whenever OpenGL, Core Graphics, Quartz Composer are in use and calls in the discrete GPU to help.

Another way Apple's method differs from Nvidia's system is that Optimus runs the discrete GPU's display through the IGP's frame buffer. This requires that both the GPU and IGP to be active, as well as taking up a lot of traffic on the bus. Apple's solution deactivates the Intel HD graphics whenever the GT 330M is called upon, helping it be a little more power friendly.

Apple credits its control over software and hardware as the main reason why it is able to offer an arguably better solution to automatically switching graphics. In fact, Apple appears to have modified the baseline HM55 Express Intel chipset to accommodate for this more advanced switching technology, according to a teardown done by iFixit.

Sadly, Apple doesn't offer the user full control over which graphics part run and when. The quoted battery life is 8 hours when running the GT 330M and 9 hours when it's Intel HD IGP only. Although the user can select between auto switching and having the GT 330M run full time, the option to disable the discrete GPU for the sake of prolonging battery life (like being able to switch off Bluetooth or Wi-Fi) doesn't exist.

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  • cabose369
    Someone should sue Apple for modifying their computers and put Steve Jobs in jail! LOL!! (see below if you don't get it)

    "Modifying a console and computer is considered an illegal act under section 342.1 of the Criminal Code and is punishable by imprisonment for up to ten years," the RCMP said in the statement.
  • Zinosys
    Mmm, interesting. I wonder what Intel has to say about this...

    But this looks neat. I don't see what's wrong with that, save the fact that you can't disable the 330 for battery purposes. Maybe we'll see a driver update in the future.

    Looks interesting nonetheless.
  • cabose369
    ZinosysSaying that Steve should go to jail is pretty far out. That's a bit silly. I really doubt anything definitive is going to happen. (as we well know, Apple's legal team knows how to bend laws a bit).

    It was a joke......