Aluminium Macbook Pro Sli?

Hi

I was wondering if anyone can help me, I wanted to ask if the new Pros are dual GPU or Sli?. Also do you think Apple will eventually enable bootcamp and XP/Vista to recognise both graphics card and utilise both?.

Sorry for the confusion but I'm confused what the two GPU aren't working in conjunction except to save battery performance etc.

 

Currently, no they're dual gpu, unlinked and separate. You use the 9400 iGPU for better battery and the 9600 dGPU for performance.

As far as I've seen, nVidia and Apple have been pretty mum so far about whether a future update might be used/able to make this hybrid SLI thing happen. I'm going to guess that *if* it happens, it's likely to be first (and maybe only) in OSX.

 

So they could utilise it in OSX?, I assumed it would have to be hardware to enable Sli. Its just strange because two cards used at the same time would have been great.

 

Remember it's not PROPER SLi though.

It's just a hybrid SLi. One integrated + one dedicated.
It's not like having TWO 9600m GT.

The difference between the 9600m GT and the 9400m integrated is SO HUGE, that even with SLi enabled, the 9400m is not going to help out the 9600M GT.

 

The 9400 is just a 9600 with half the processing cores and slightly underclocked. You are looking at 54 Gflops vs 120 Gflops. So SLI has the potential to increase performance ~40% which is hardly insignificant.

 

It's not even Hybrid SLI since Hybrid SLI has little relation to SLI. GeForce Boost is the ability to combine the IGP and a discrete GPU. HybridPower is the dynamic switching. Hybrid SLI is just some marketing term encompassing both ability to describe their platform.

http://www.barefeats.com/mbpp07.html

In any case, I have to agree that enabling GeForce Boost is a waste of time. The Gigaflop numbers are really realistic for games since that's just theoretical processing power and real bottlenecks are memory bandwidth, texture units, and the like. Besides, the 9400M's figures would be highly variable anyways depending on how much memory bandwidth the CPU is stealing. The 9400M is like 25% of the 9600M GT in actual games, but having the overhead of SLI, especially since it's operating asynchronously because they aren't the same GPU, means a 10-15% boost is more realistic.

What Apple is going to do in Snow Leopard is incorporate Grand Central which allows processing tasks to be distributed to all CPUs and GPUs in a system. Only games require both GPUs to be combined to appear as one. In Grand Central both GPUs will remain discrete and can operate independently. This is more advantageous anyways since you save overhead. This mainly for number crunching tasks like rendering and won't increase a game's fps directly.

However, a game could use the main GPU for graphics rendering and the IGP for physics calculations. This is what nVidia has done with allowing GPU PhysX acceleration on the weaker GPU with main GPU doing the graphics. I've actually emailed MacSoft about hardware GPU PhysX acceleration for their Mac port of UT3 including the ability to use the IGP for PhysX and discrete GPU for rendering. It's kind of late in the development cycle since I think they are targeting to get it out in time for Christmas, but I suggested that they try to add it in a later patch or in the Mac port of the UT3 Expansion that Epic has announced. MacSoft replied and said they've passed it on to their development team to look into so we'll see if anything comes out of it. It may well have to wait until Snow Leopard though since I don't know if Leopard has the architecture to run both GPUs at the same time and schedule tasks between them.

 

Also I'm pretty sure the 9400M (integrated) is not the same as the 9400M GT (dedicated). So don't benchmark it like that.

 

Are you referring to my Barefeats link since that was done on the 9400M IGP on the MacBook Pro.