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Old Dec 14, 2012, 06:49 PM   #1
Jonnybeats
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2012 iMac - Graphics Switching?

Hi guys,

Just out of curiosity, do any of you guys know if the new 2012 iMac features the same graphics switching system as the new MBPs.
I didn't see it noted anywhere on the Apple website.

The concept for those of you unfamiliar is that the computer will only run the Nvidia discrete graphics chip when the computer is under load, reverting back to the Intel integrated graphics processor during less intensive tasks to save power.

I'm not particularly fussed if it does or doesn't but it'd be a nice touch if it was featured on the iMac to reduce heat at idle.

Cheers.

--

Damn iMac, arrive already... I can't wait until Wednesday!!
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Old Dec 14, 2012, 07:28 PM   #2
bflowers
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Apple support doesn't mention the 2012 iMac in the list of systems with both types of GPUs in use. There was no mention of it on the current iMac page.

http://support.apple.com/kb/HT3246
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Old Dec 14, 2012, 07:57 PM   #3
Gelite55
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No. I don't think so. It's a Desktop so power really isn't a issue.
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Old Dec 14, 2012, 09:00 PM   #4
joe-h2o
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Quote:
Originally Posted by Jonnybeats View Post
Hi guys,

Just out of curiosity, do any of you guys know if the new 2012 iMac features the same graphics switching system as the new MBPs.
I didn't see it noted anywhere on the Apple website.

The concept for those of you unfamiliar is that the computer will only run the Nvidia discrete graphics chip when the computer is under load, reverting back to the Intel integrated graphics processor during less intensive tasks to save power.

I'm not particularly fussed if it does or doesn't but it'd be a nice touch if it was featured on the iMac to reduce heat at idle.

Cheers.

--

Damn iMac, arrive already... I can't wait until Wednesday!!
Absolutely not.

The CPU models that Apple has chosen for the iMac specifically exclude the more powerful integrated GPU - ie, they went for the cheaper "CPU only" i5's and i7's with the really old style token integrated parts (not the HD4000).

There is no need for automatic graphics switching, since at idle the main GPU
isn't even breaking sweat and under load you want the GPU to be doing the heavy lifting. There's simply no need to power down the dedicated GPU at idle or low loads since the only real benefit is battery life extension, and potentially heat reduction. Given that the iMac is virtually silent at low loads (ie, it's running quite cool enough) and doesn't have a battery to worry about switching to the integrated GPU is unnecessary.
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Old Dec 15, 2012, 08:45 AM   #5
Jonnybeats
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Quote:
Originally Posted by joe-h2o View Post
There's simply no need to power down the dedicated GPU at idle or low loads since the only real benefit is battery life extension, and potentially heat reduction. Given that the iMac is virtually silent at low loads (ie, it's running quite cool enough) and doesn't have a battery to worry about switching to the integrated GPU is unnecessary.
Yeah, that was my thinking.

Thanks for you input.
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Old Dec 15, 2012, 09:57 AM   #6
theSeb
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Quote:
Originally Posted by joe-h2o View Post
Absolutely not.

The CPU models that Apple has chosen for the iMac specifically exclude the more powerful integrated GPU - ie, they went for the cheaper "CPU only" i5's and i7's with the really old style token integrated parts (not the HD4000).
The reason why Apple chose these CPUs is pretty clear. It's because there is no need for integrated graphics in an iMac. It's completely disabled.

Let's compare from the same family. The 27" "high-spec" (not the ultimate BTO) has an i5-3470. Here it is

http://ark.intel.com/products/68316/...up-to-3_60-GHz

It does indeed only have an HD2500. Because Intel expects any one using the CPU to include discrete graphics.

Tray price? 184$

If they went for the more expensive 3475s with the HD4000, what exactly would be the point?

Tray Price? 201$

What do we get? Clock Speed 2.9 GHz Max Turbo Frequency 3.6 GHz

So the normal clock speed is actually slower than the CPU that was included in the iMac. It's actually better for the consumer that Apple chose this CPU over the one with the HD4000. The HD4000 is useless when the integrated graphics is disabled anyway.
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Old Dec 15, 2012, 11:50 AM   #7
joe-h2o
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Quote:
Originally Posted by theSeb View Post
The reason why Apple chose these CPUs is pretty clear. It's because there is no need for integrated graphics in an iMac. It's completely disabled.

Let's compare from the same family. The 27" "high-spec" (not the ultimate BTO) has an i5-3470. Here it is

http://ark.intel.com/products/68316/...up-to-3_60-GHz

It does indeed only have an HD2500. Because Intel expects any one using the CPU to include discrete graphics.

Tray price? 184$

If they went for the more expensive 3475s with the HD4000, what exactly would be the point?

Tray Price? 201$

What do we get? Clock Speed 2.9 GHz Max Turbo Frequency 3.6 GHz

So the normal clock speed is actually slower than the CPU that was included in the iMac. It's actually better for the consumer that Apple chose this CPU over the one with the HD4000. The HD4000 is useless when the integrated graphics is disabled anyway.
That was my whole point :P

There is no GPU-free i5 or i7 in the consumer range - they all have at least the old weaksauce one, or the HD4000. As you said, there's no reason to get the one with the HD4000. It costs more and is less effective. The dedicated GPU alone is fine for all operating modes.
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