Apple's automatic graphics switching - not Optimus, but is it better?

This article from ars technica is probably a good place to start.

Up until recently, many suspected that Apple was just using Nvidia's Optimus technology for its new 15" and 17" MacBook Pros. However, there are key differences which prove this cannot be the case, and Apple themselves have said their technology is different. Unlike Optimus, which sends data from the discrete graphics to the IGP framebuffer, and hence needs to keep the IGP on in discrete graphics mode, Apple's solution powers down the IGP entirely. This means that Apple must actually be using a hardware multiplexer at the back end, just like in all switchable graphics before Optimus.

As far as I can tell, Apple seem to have pulled a coup d'etat with their multiplexer, though, because their switching is supposedly just as seamless as Optimus. I'm guessing that Apple runs both adapters for a short time before making a transition in order to avoid a noticeable delay or flickering. I'd be interested to see how they got over the issue of blocking programs, though.

In any case, Apple's solution has the clear advantage of lower power consumption when running the discrete graphics. However, this comes at the cost of being entirely reliant on Apple's proprietary technology. In particular, Apple hasn't released switchable graphics drivers for Windows, so you're stuck with discrete graphics only if you have some need for dual-booting with Windows. Additionally, Apple's technology doesn't seem to give you a way to change which applications run on which GPU. This means that even if you have a 3D application that you know will run well enough on Intel's GMA HD, you're still stuck using the discrete GPU.

 

Food for thought. We should see a slew of Nvidia Optimus vs. Apple Switchable Graphics crop in the coming weeks. I'm sure the tech websites are working on it. Battery life comparisons, performance benchmarks, and visual diagrams would be a start.

 

As far as battery life is concerned, most tests and ratings for these laptops would be run only on the integrated graphics anyway, and so the different approach to switchable graphics wouldn't matter for those.

However, I have seen some interesting results for Optimus here, where the laptop actually got slightly better battery life with Optimus on than when using only the IGP. Granted, the discrete GPU here was the 310M, which is a lot less power-hungry than the 330M, but I would guess that unless there were issues with the testing, the lower power consumption was due to the 310M taking a lot of load off the CPU.