Dual gpu on 2011 iMac for all model?

iSayuSay

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Feb 6, 2011
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Sorry if my thread title a lil bit misleading. But i reAlly want tO know your opinion about this.

iMac always come with separated GPU with dedicated memory on every model. Now since 2011 iMac most likely use intel Sandy Bridge which include intel hd3000 gpu with 384mb shared memory, does that mean newer imac will use both gpu for 3d/graphic processing?

Or hd3000 gpu will be wasted or ignored since the imac has its own gpu? Yeah i know intel hd3000 kinda suck compared to new radeon, but at least the system can use it for basic rendering, while heavy rendering stuff can be loaded to the main gpu.

Same case just like the new topline of MBP which has radeon 6450, does that mean 6450and hd3000 from intel work together as if they are crossfired?

Thx in advancw for your answer/opinion
 

Hellhammer

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Dec 10, 2008
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In MBPs, you can use either the IGP or discrete chip. You cannot use them simultaneously. Apple would have to use Lucid Virtu to enable simultaneous use but that is still very new technology and most likely Windows only. Even then, the IGP is only useful if QuickSync is supported (currently supported by two Windows apps). In games it performs worse.

Most likely the IGP will be ignored as there isn't much real world use for it.
 

iSayuSay

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Feb 6, 2011
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Sorry for bumping my old thread, but instead of making new topic, I decide to continue this one since the question is related.

Now we have 2011 iMac with Sandy Bridge, which we know the processor itself has its own IGP on chip.

Hellhammer answered clearly that I wouldn´t be able to use both GPU at the same time

But how about choose one? Of course Radeon 6 is waaay better than IGP on the processor itself. But can we do the switch to choose which GPU we would like to use?

It would be handy in the situation when your main GPU is failing. we could swith to IGP, do backup, or even working temporarily before we bring them in for warranty claim.

Is that possible? Or the IGP on chip is just obsolete?
 

Icy1007

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Feb 26, 2011
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The iMac is a desktop, why would you want to be able to use the integrated HD 3000 graphics? The main purpose for having the two graphics chips usable on the MacBook Pro is to save battery power when the discrete graphics aren't needed. Since the iMac is always plugged in and has no battery, there is no point in it being used.
 

dh2005

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Jan 25, 2010
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It's nonetheless interesting to know. And, as the OP said, it may be helpful for troubleshooting.
 

Jorojr

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Dec 10, 2008
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On the 6970 iMac, there is no integrated graphics at all.
This is incorrect. The graphics core is part of the Sandybridge design itself. If the chipset (P67) doesn't have Intels Flex Display Interface, the integrated graphics subsystem is ignored. It's a different story with the H67 and Z68 chipsets which has this interface. As others have said, there is no real usage for it so it is going to be just ignored.
 

iSayuSay

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Feb 6, 2011
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So even the IGP itself is exist on processor chip, but the imac board design doesn't let the IGP utilization?

Well like i said, of course there almost no reason for using IGP on imac since discrete GPU is much much better

But it's nice if we have backup GPU in case radeon is failing.
 

Zen0Jin

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Feb 1, 2011
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This is incorrect. The graphics core is part of the Sandybridge design itself. If the chipset (P67) doesn't have Intels Flex Display Interface, the integrated graphics subsystem is ignored. It's a different story with the H67 and Z68 chipsets which has this interface. As others have said, there is no real usage for it so it is going to be just ignored.
Um, no. The point is neither OSX nor Windows recognizes the existence of the integrated graphics on my Core i7 2600.

The Z68 which these iMacs use allow for the intel 2000/3000 to be used, but Apple does not. Simple as that.
 

archer75

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Jan 26, 2005
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The hardware is there. Sandy bridge does have an integrated gpu and the z68 chipset supports it as well. Wether or not we may be able to access it for those few apps that support it is a different story. Apple may very well have disabled access to it.
 

Hellhammer

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Dec 10, 2008
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The Z68 which these iMacs use allow for the intel 2000/3000 to be used, but Apple does not. Simple as that.
Only if you don't have a discrete GPU. Since all iMacs have dGPU, the IGP is disabled because there is no monitor connected to it. Like I said before, Apple would have to use a technology like Virtu or other GPU switching tech to allow the IGP to be enabled even without a monitor connected to it.

Whether this can be updated via OS X/firmware update, that I don't know, but it looks like Apple is not interested in this.
 

iSayuSay

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Feb 6, 2011
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Only if you don't have a discrete GPU. Since all iMacs have dGPU, the IGP is disabled because there is no monitor connected to it. Like I said before, Apple would have to use a technology like Virtu or other GPU switching tech to allow the IGP to be enabled even without a monitor connected to it.

Whether this can be updated via OS X/firmware update, that I don't know, but it looks like Apple is not interested in this.
Wow you came from Hell, but always have been helpful as an angel, what an irony :D

Thanks for clear things up, and also for others, been really helpful :D