The new notebook has been graced with the presence of NVIDIA’s newest card, the GeForce 9400M a whole day before its official release (that’s what you get when you’re Apple). They say the thing is up to five times faster than the practically lethargic Intel GMA3100 included in the old models. The MacBook Pro also contains the 9400M, which is a nice addition, but hardly worthy of being the GPU of a Pro notebook on its own. To fulfill that role, they’ve included the higher-end GeForce 9600M GT*.

The Unused GPU

Having a nice, fast GPU is all well and good if you’re playing games, but the vast majority of MacBook Pro users’ work doesn’t use the GPU hardly at all.

Even worse, the unibody MacBook Pros can only use one GPU at a time, regardless of what you’re doing with it, and requires a fair bit of sacrifice to switch between them. Perhaps you don’t mind having to log out to switch GPUs, but it doesn’t really demonstrate the seamlessness that Apple seems to aim for. I fully expect this to change in a future Leopard software update, however.

As great as such an update would be, it still would only allow you the use of one GPU. The really impressive thing will be when Apple allows you use of both GPUs at once in some fashion of Hybrid-SLI. While there’s always the chance that this will be enabled in Leopard, I don’t have much hope of this happening before the release of Snow Leopard next year.

I say this for a couple of reasons. Number one, I’m guessing it requires a rather extensive overhaul of Apple’s window manager and graphics subsystem to use two GPUs at once and actually increase performance. They’re already doing extensive overhauls of everything else for Snow Leopard, so that’s a great opportunity to improve this as well.

UPDATE 10/23: MacRumors claims to have received information from NVIDIA confirming that the MacBook Pros are capable of doing this (a feature they call GeForce Boost). They also confirm that the machines are capable of switching between on-the-fly, which, as they say, should not be surprising since the same functionality is available under Windows. I have absolutely no doubts at this point that both of these features will be available by the time Snow Leopard rolls around.

OpenCL, Grand Central, and the GPU

Number two, and most importantly, Snow Leopard includes a technology called OpenCL, which (theoretically) allows developers and OS X itself to offload queued processing to the GPU. GPUs tend to be significantly faster than CPUs for a relatively select group of tasks, but these tasks should see gargantuan performance leaps when running under Snow Leopard.

With OpenCL offloading processing tasks to the GPU, a lot of possibilities start opening up. Apple’s also pitching a Snow Leopard technology called Grand Central, which chops up OS X’s own processing tasks for running on multiple cores, and also has provisions for allowing developers to access the same power.

Combine OpenCL and Grand Central into some multicore-GPU-supporting technology, and suddenly Snow Leopard has one more processing unit to work with. Granted, this new core may not be as fast as the CPU for some tasks, but is also potentially much faster than the CPU for others.

There was a lot of negative commentary on AMD’s decision to produce triple-core processors; even I thought it was a rather counter-productive strategy. But come Snow Leopard in 2009, Apple will be enabling a third core on a whole lot of its Macs (pre-October-2008 non-Pro MacBooks excepted).

The MacBook Pro is Apple’s first Mac with two GPUs, and will give OpenCL twice as many processing units to work with. This gives a total of — count them: two cores in the Core 2 Duo, one more in the NVIDIA 9400M, and yet another in the 9600M GT. Four processing cores in Apple’s current-generation notebooks.

Granted, the extra two may not be very useful in every situation. But neither GPU is a slouch, and either will provide huge benefits in a lot of graphically-related situations. Generally speaking, perhaps technically speaking too, and for all practical purposes, the Late 2008 MacBook Pro has four cores. Apple’s first quad-core Mac notebook.

* Widely accused of being a repackaged 8600M GT, Notebookcheck benchmarks claim the 9600M GT is 50% faster than the last-generation 8600M GTs on 3DMark06 and 43% faster on 3DMark05. It also includes new technologies like PureVideo HD (that Apple may or may not be taking advantage of) and is manufactured wth a 65nm process, compared to the 80nm process of the 8600M GT. I don’t know much about GPU benchmarks, but that seems significant enough to me.