New iMac Video card stealth upgrade: mobility Radeon HD 2600 XT?

I'm going to mark this one rumor for right now, but there's an interesting thread going on over at MacRumors Forums that suggests that the new iMacs may have a stealth upgrade. When they were announced a lot of folks were disappointed with the included Radeon HD 2600 Pro graphics card, however, some people have discovered that (at least running Windows in Boot Camp) their machines appear to be reporting that the GPU is actually an underclocked mobility Radeon HD 2600 XT, which is a more powerful chip. This would not be the first time that Windows has revealed hardware that Apple wanted hidden, as several machines were discovered to have draft 802.11n wireless networking chipsets in that way before they were later activated by Apple. Many are expressing hope that some future update or some ATI specific tool might unlock the hidden power of the GPU, but at this point it seems to be wishful thinking.
Thanks Marin!
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Reader Comments (Page 1 of 1)
Ryan said 6:56PM on 8-29-2007
I think everyone knows by now that this chip is not what they say it is. That thread has been going on nearly a month now, so it's not news. One of the first things I did when I checked out the machines at the apple store when they came out was to see how much cpu was sucked up watching 1080p trailers. The answer was too much for the chip being utilized by proper drivers. It's supposed to have full h.264/avc gpu decoding, but yet the cpu was running 50%. So I asked the people there if this is going to be corrected by driver updates and/or leopard since these chips aren't performing as advertised. They said they had no idea. Figures. That plus the ddr3 ram instead of 2 as with other models of the same name made it all seem like magical software updates in the future would all give us massive speed boosts and Apple some bragging rights about their great software and engineers. Basically iPod video all over again.
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J Baden said 7:46PM on 8-29-2007
Perhaps I don't understandd what is referred to by the "hidden power" of the GPU being unlocked, because wouldn't a simple bios speed hack work to increase the GPU clock and memory speeds? I did that to both my Macbook Pro X1600 and my Mac Pro X1900 that were also underclocked by Apple.
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Quix said 8:23PM on 8-29-2007
I hope this rumor turns out to have merit, as the video cards were my one and only disappointment with the new iMacs (oh, and why can't Apple add more USB ports???).
I refuse to replace my current iMac (the first Intel model) with a new model until Apple does something about the wimpy video processors.
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Chris said 8:36PM on 8-29-2007
Ryan - I'm quite certain that Apple has never advertised that the new iMac (or newest MacBook Pros) uses the video card for hardware h.264 decoding. The ATI 2400/2600 and NVidia 8600 definitely support it, but it's probably not just the drivers that need to be updated - it's likely to require significant changes to QuickTime as well.
Since Apple has not publicly released any info on whether or not Leopard will include h.264 hardware decoding, or if changes in Leopard will allow that possibility, there's no way for us to know until Leopard is released, since that info would be under NDA (non-disclosure agreement). Employees of an Apple Store (or other store) probably don't have developer access to Leopard, and if they did, they probably wouldn't break the NDA to answer your question.
In the meantime, the new iMacs should have no problem playing back at least 2-3 1080p h.264 videos simultaneously with no dropped frames. Of course, I hope hardware decoding becomes available as soon as possible...
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danny bogue said 10:02PM on 8-29-2007
uh i remember them telling us that it WAS the HD 2600 XT on the keynote....
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John said 10:15PM on 8-29-2007
Not impressed, and not surprised.
They tried this same trick on the first Mac mini to reduce heat, and ended up flubbing DVI-D output for some people. Aesthetics over performance once again.
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Michael said 11:38PM on 8-29-2007
I am on a G3 imac at the moment and waiting for leopard to come out to buy a new imac. Any thing would be an improvement over what I have now.
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Mo said 3:14AM on 8-30-2007
@6: Reducing heat is hardly “aesthetics”.
There are usually sound reasons for shipping underclocked chips: drivers might not be stable yet, or the thing runs too hot and causes problems for the system as a whole, or there are stability problems.
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Adam said 4:00AM on 8-30-2007
Don't trust what boot camp tells you
Apparently my 2.2Ghz MacbookPro w/ 128MB 8600GT, has 512MB, which I am positive is not true (it has 128MB, not 512)
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jason said 12:25PM on 8-30-2007
#9 Adam
If you read the whole 21 pages of of the thread over at MacRumors (not likely, I know... I don't blame you), it seems to have been "confirmed" via several other methods other than Boot Camp.
But to be honest, I only skimmed the thread.
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AlexP said 4:47PM on 8-30-2007
Um, I was under the impression that I was getting the same driver error that made my X800 XT a simple X800 back in 04 after buying my new PC. I really, really doubt it's an XT.
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RRK said 9:57AM on 8-31-2007
Even Apples System Profiler states that the "Device ID: 0x9583". This ID refers to the mobility 2600 xt.
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TBi said 10:12AM on 8-31-2007
"Apparently my 2.2Ghz MacbookPro w/ 128MB 8600GT, has 512MB, which I am positive is not true (it has 128MB, not 512)"
In windows your graphics card uses "TurboCache" which basically means it uses system memory as graphics memory. This is the same as how the GMA in a Macbook has 128MB memory when in reality it has none.
So too all extents and purposes you have a graphics card with 512MB of slower than normal graphics ram. OSX doesn't use this feature though. This would need a lot of driver development and probably some changes to how OSX handles graphics cards.
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DJ said 6:21PM on 9-04-2007
Its funny but I went to the local apple store in Connecticut and they only had the 20 inch 2.4 GHZ imacs with 2MB of ram in it and not the boxed version(1mb) that a consumer would buy? Plus there were NO 2.0 GHZ 20 inch models on the floor. So it seems there is some trickery going on directed at the dumb consumer who does not know to look at the drop down "about this imac". I asked the store employee why there were no 2.0GHZ imacs on the floor, he said "nothing". Put the real deal on the floor and leave it up to the consumer to upgrade!!
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