

IPad 2: GPU Benchmarked with Impressive Gains - topgeek
http://www.macrumors.com/2011/03/12/ipad-2-gpu-benchmarked-with-impressive-gains/

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jrockway
To be fair, the Xoom has 1.3x as many pixels as the iPad. The iPad 2 is still
faster taking this into account, but the graph is misleading.

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YooLi
Misleading how? It's an FPS graph between devices. Do you want to scale the
Xoom score? It will still be more than doubled by the iPad 2.

~~~
ZeroGravitas
Check out this graph with more devices:

<http://images.anandtech.com/graphs/graph4191/35571.png>

Tegra2 phones do better than Tegra2 tablets and the iPhone4 does better than
the iPad 1. Look how well the iPhone 3GS does due to its lower resolution.

In short, higher resolution screens are penalised by this benchmark.

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ugh
Uhm, yeah. But how is that relevant? The Xoom actually has that many pixels.
The whole package matters.

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ZeroGravitas
So your takeaway from this is that iPhone 3GS has a better GPU than the iPad?
Or that it's a better "package" than the iPhone 4?

It's a benchmark. If you don't know what it's actually measuring then you
might as well not bother.

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ugh
My takeaway is that you can expect better graphics performance on an iPhone
3GS than on an iPad 1 or iPhone 4, yes. If you are not designing tablets and
deciding what GPU to put in there, comparisons between GPUs are completely
meaningless. You have to look at the whole device.

Looking at GPUs in isolation in tablets is about as meaningless as looking at
their batteries in isolation. How many watt-hours they have is only a poor
proxy for their runtime.

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ZeroGravitas
Well, I have to admit I'm surprised that you're saying that the iPhone 4 has
worse "graphics performance" than such classic phones as the Nokia N900, the
famously GPU-poor Nexus One, the venerable Motorola Droid and the cheapo
Optimus One.

And I'm not even bothering to mention any device in the top half of the table
that all beat even the amazing 3GS. But if you're that determined to argue
that the iPhone 4 and iPad as a package suck at "graphics performance" to the
extent shown on that link I provided then who am I to argue with such a
revelatory benchmark. Those Android guys must really have their act together
when it comes to holistic design.

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ugh
The only alternative that I see is that the benchmark is rubbish.

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bluekeybox
It appears that Tegra 2 is missing the ARM NEON SIMD engine
([http://www.anandtech.com/show/4144/lg-optimus-2x-nvidia-
tegr...](http://www.anandtech.com/show/4144/lg-optimus-2x-nvidia-
tegra-2-review-the-first-dual-core-smartphone/8)) which the iPad 2's A5 chip
supposedly has (someone please confirm this report:
[http://pdadb.net/index.php?m=cpu&id=a50000&c=samsung...](http://pdadb.net/index.php?m=cpu&id=a50000&c=samsung_apple_a5)).
This would explain the benchmark discrepancy. There is another benchmark
(<http://www.pcmag.com/article2/0,2817,2381767,00.asp>) that shows that A5 is
3x faster at matrix operations than Tegra 2, while being 1.5x slower executing
code that likely does not involve matrix/vector operations.

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DarkShikari
Yes, Tegra 2 is missing NEON. I can't comprehend why people still release CPUs
intended for any kind of performance yet omit the SIMD engine -- my suspicion
is nVidia is trying to encourage developers to use their GPU APIs instead by
crippling the ability of the CPU to do number crunching.

I highly doubt it's an overly significant power or die size issue -- with the
amount they're already spending on L1 cache, L2 cache, and so forth, it seems
dumb to omit the kind of powerful ALU necessary to make use of it all.

~~~
rsynnott
Tegra 2 doesn't support OpenCL or CUDA, though Tegra 3 will. The PowerVR
SGX543 supports OpenCL, though not, of course, CUDA.

EDIT: At the time, NVidia claimed that it _was_ a die size limitation.

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abuzzooz
I don't know if there is much to deduce from these benchmarks. They are good
for bragging rights, that's for sure. But that's about it.

Note also that while the Xoom is a new product, its Tegra 2 processor is
relatively old. NVIDIA first demoed it in January 2010. So here they're really
comparing apples to oranges.

In any case, good for Apple. The iPad 2 does look like a good product.

~~~
ghshephard
I agree that comparing the GPUs is a little unfair, but the iPad and Xoom were
released within a several weeks of each other, so I think it's entirely fair
to compare system graphics performance.

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wtallis
Things like this show that we need a change of mindset when evaluating the
technical capabilities of embedded devices instead of PCs. When a new graphics
chip is released, you can't swap it for your old GPU, and it won't show up as
a build-to-order option in 3 weeks, either. You have to wait for it to be
integrated in to new SoCs.

Trying to excuse the Xoom's obsolete GPU (particularly when the Xoom's biggest
selling point is the higher resolution screen) makes no more sense than trying
to compare a current product to the announced but not shipping Cortex A15
processor.

