MacBook Pro Does Not Support Both GPUs Simultaneously

[MacRumors]

When Apple introduced new MacBook Pro notebooks with two types of Graphics Processing Units (GPUs) from NVIDIA, many wondered if both GPUs could be used simultaneously. NVIDIA's Hybrid SLI technology allows some notebook configurations to use one or both of a notebook's GPUs. When both GPUs are utilized simultaneously, the user can see dramatic performance boosts.

NVIDIA has since clarified that the new MacBook Pro only supports the ability to switch between the integrated and discrete GPUs for power conservation, but does not allow the use of both at the same time:

Apple's Macbook Pro (Late 2008) does feature both the NVIDIA® GeForce®9400M motherboard GPU for everyday computing and the NVIDIA® GeForce® 9600M GT discrete GPU for high graphics performance. You can switch between the Geforce 9400M motherboard GPU (called energy saver mode) and the Geforce 9600M GT discrete GPU (called performance mode), but you cannot use both GPU's at once in this implementation.

In fact, it's been revealed that switching between the two GPUs on the MacBook Pro requires the user to log out of Mac OS X. Apparently, other implementations of NVIDIA's Hybrid SLI allows on-the-fly switching between GPUs, so it's not clear if this limitation in the MacBook Pro is a software or hardware issue.

With the inclusion of NVIDIA GPUs in both the MacBook and MacBook Pro, Apple has positioned most of its computers well to accommodate the next version of Mac OS X called Snow Leopard which will be able to take additional advantage of the GPUs.


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[timswim78]

That stinks.

I wish that the implementation of the NVIDIA system was similar to what AMD's 780G chipset has, allowing hybrid SLI with the integrated video and a discrete video chip.

Hopefully, Grand Central in 10.6 will be able to use both GPU's. If not, it seems kind of silly to have two chips.

[infernohellion]

Seriously?

This surely would slow down my purchase on the upcoming 17". My guess is we probably have to wait for the next Leopard update or even Snow Leopard.

[lamina]

I was waiting for that one caveat that would make the new MBP less desirable to me. It's a small one, but still chips away at my justification for a new Mac

[840quadra]

Engadget has found that the performance of the discrete to be a bit higher than expected. Not calling Apple or nVidia wrong, but I highly doubt that we have a "special" implantation of this graphics platform.

[raggedjimmi]

Aw bugger, I wowwed when I first head about the dual GPU thingy. Now it's not so good. Hope it gets resolved as it would seriously bump up the capabilities of the MBP.

[decimortis]

Not a huge deal to me, but it's added to list of reasons why I'm waiting for the rev B. The biggest reason being I don't have the coin at the moment.

[lamina]

Originally Posted by timswim78

Hopefully, Grand Central in 10.6 will be able to use both GPU's. If not, it seems kind of silly to have two chips.

I have a feeling that these new Macs are more forward-looking than we give them credit for. I think a lot of Snow Leopard and even 10.6 will take full advantage of things that Leopard as it is today won't address.

[Keleko]

This sounds like it is only true for OSX. Some testing I read about with Crysis showed that it may indeed actually use SLI from a Windows install on the same system.

[andiwm2003]

does that mean one GPU is on and the other chip is inactive?

what I'm asking is can the 9400 be used as a GPU while snow leopard uses the 9600 for non graphics tasks like transcoding or heavvy calculations in the background?

that would be the real performance boost I would be interested in.

[arn]

Originally Posted by Keleko

This sounds like it is only true for OSX. Some testing I read about with Crysis showed that it may indeed actually use SLI from a Windows install on the same system.

Actually, NVIDIA says no
http://nvidia.custhelp.com/cgi-bin/n...p?p_faqid=2243

When running Microsoft's Windows XP™ or Microsoft's Windows Vista™ using Apple's Boot Camp, the system locks into performance mode which uses the Geforce 9600M GT discrete GPU for all graphics related tasks and can not be changed to use the Geforce 9400M motherboard GPU for low power mode.

[fluidedge]

honestly what was the point of putting 2 GPUs into the MBP again?? I thought Ive said "nothing that doesn't need to be in there isn't!"

Apple have really messed the notebooks up. I'm not one of the "they're abandoning pros" type of people but they ARE abandoning pros.

[840quadra]

Originally Posted by andiwm2003

does that mean one GPU is on and the other chip is inactive?

what I'm asking is can the 9400 be used as a GPU while snow leopard uses the 9600 for non graphics tasks like transcoding or heavvy calculations in the background?

that would be the real performance boost I would be interested in.

That is a good point.

I am also wondering if the inactive graphics chipset is utilized by the external monitor for desktop expansion / mirroring. That would be a nice feature too, leaving the one GPU chugging a presentation while the other is almost idle providing the presenter with notes or controls to the presentation.

I don't have an adapter for my Display port yet, but it is something I want to test!

Regardless,

If Apple did not make this system capable of using both GPUs in Snow Leopard, I will be highly disappointed by that accidental (or purposeful) misstep.

[Rocketman]

I think it is fair to say Snow Leopard is the implementation of that which allows dual use. I am wondering how many processors as an option the 17" will have? Internal Raid too?

Rocketman

[pismodude2]

What do I care? I'm getting a MacBook! Oh, yeah! Finally, a MacBook with an ACTUAL graphics card! Say bye, bye to the 'integrated' crap!

[cv01]

Originally Posted by pismodude2

What do I care? I'm getting a MacBook! Oh, yeah! Finally, a MacBook with an ACTUAL graphics card! Say bye, bye to the 'integrated' crap!

It is still an integrated one!

[MarcBook]

Technically the MacBook's 9400M is integrated, but it's still waaaayyy better than the Intel equivalent.

[cv01]

OT: Apple confirms that there will be no adapter for old video-output-ports for the new 24" LED Cinema Display (http://www.fscklog.com/2008/10/24-led-cinema-d.html)

[Fredd-E]

http://nvidia.custhelp.com/cgi-bin/n...p?p_faqid=2243

This support doc states that currently it is not possible two have the two gpu's work at the very same time in the new Apple notebooks.

But, they also say: "Apple's hybrid graphics technology is supported under the MacOS X operating system version 10.5.6 and higher only." Am I reading this wrong or are they saying that when 10.5.6 is released it will support the method of two gpu's working at same time? Or will it be supported when Snow Leopard (10.6) is released?!

[arn]

Originally Posted by Fredd-E

http://nvidia.custhelp.com/cgi-bin/n...p?p_faqid=2243

This support doc states that currently it is not possible two have the two gpu's work at the very same time in the new Apple notebooks.

But, they also say: "Apple's hybrid graphics technology is supported under the MacOS X operating system version 10.5.6 and higher only." Am I reading this wrong or are they saying that when 10.5.6 is released it will support the method of two gpu's working at same time? Or will it be supported when Snow Leopard (10.6) is released?!

Hybrid Graphics = turning off one GPU or the other. Apple supports this. IT does not support the use of both gpus (GeForce Boost mode)

arn

[McBeats]

really? then who cares... my next bit of money is goin to a new mac pro now...

[Fredd-E]

Originally Posted by arn

Hybrid Graphics = turning off one GPU or the other. Apple supports this. IT does not support the use of both gpus (GeForce Boost mode)

arn

Ok, that's clear. But why do they state 10.5.6 (or higher) then when that's not even out yet? I don't get it. (Mind I don't own a mac yet, my girlfriend does, and afaik her imac is up to date on 10.5.5).

[slackpacker]

Yes my Benchmarks using the old standby Xbench dont seem to change when switchng CPU's. I wish there was another good benchmark that was Free. GeekBench charges money for a benchmark tool... any others free>?

[840quadra]

Originally Posted by arn

Hybrid Graphics = turning off one GPU or the other. Apple supports this. IT does not support the use of both gpus (GeForce Boost mode)

arn

So in other words that 10.5.6 statement is an incorrect point in the nVidia FAQ? My new MBP is currently running 10.5.5 (Edited for clarity. Initially thought it shipped with 10.5.4 but misread log files), and this version obviously allows switching between GPUs.

[arn]

Originally Posted by 840quadra

So in other words that 10.5.6 statement is an incorrect point in the nVidia FAQ? My new MBP is currently running 10.5.5 (BTW they don't ship that way, I had to upgrade it when I unboxed it), and this version obviously allows switching between GPUs.

That doesn't sound right. What version of Mac OS X did it come with? 10.5.4? (seems unlikely)

The new MacBook Pros (as do all new Macs) ship with a special version of Mac OS X to support it. These changes are integrated into the next major Mac OS X release (10.5.6).

arn