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Asus Eee Pad Transformer TF101: A Tablet In Disguise

GPU Performance: Nvidia Tegra 2

As we’ve mentioned in the past, mobile devices like smartphones and tablets use what’s known as a system-on-chip (SoC). This integrates the processor, GPU, RAM, and several other subsystems onto single device. Since all of those components sit next to each other on the same chip, there is greater efficiency in data transfers, while reducing the amount of space consumed on the PCB.

Apple A4 (iPad)Apple A5 (iPad 2)Tegra 2 (Xoom/Iconia A500/Eee Pad Transformer)
Processor1 GHz ARM Cortex-A8 (single-core)1 GHz ARM Cortex-A9 (dual-core)1 GHz ARM Cortex-A9 (dual-core)
Memory256 MB 333 MHz LP-DDR (single-channel)512 MB 1066 MHz LP-DDR2 (dual-channel)1 GB 667 MHz LP-DDR2 (single-channel)
GraphicsPowerVR SGX535 (single-core)PowerVR SGX545MP2 (dual-core)ULP GeForce (single-core)
L1 Cache(Instruction/Data)32 KB / 32 KB32 KB / 32 KB32 KB / 32 KB
L2 Cache640 KB1 MB1 MB

Tegra is Nvidia’s SoC brand, and it represents the company’s effort to tap into the mobile market beyond its desktop-derived GeForce graphics processors. For those unfamiliar with Tegra 2, read page eight of our Motorola Xoom review for a full discussion on GPU architecture. On the CPU side, Tegra 2 shares the same dual-core Cortex-A9, which is a substantial boost from Cortex-A8 seen in the first-generation iPad. Check out Apple's iPad 2 Review: Tom's Goes Down The Tablet Rabbit Hole for a full discussion of Cortex-A9 performance.

While we've already covered Tegra 2, it's important to examine the graphics performance of each tablet. Sy Choudhury, director of product management at Qualcomm, states, "There is a misconception that the same processor and operating system gives the same performance." We run into that issue every time we review a tablet. Why is it wrong to expect the same performance from all Honeycomb-based Tegra 2 tablets? Hardware vendors get access to the same optimizations from the SoC developer, but not all of the software-based tweaks are enabled by OEMs.

GPU (System-on-Chip)PowerVR SGX 535(Apple A4)PowerVR SGX 543(Apple A5)ULP GeForce (Tegra 2)
SIMDUSSEUSSE2Core
Pipelines2 (unified)4 (unified)8 (4 pixel / 4 vertex)
TMUs222
Bus Width (bit)646432
Triangle rate @ 200 MHz14 MTriangles/s35 MTriangles/s?

The ULP GeForce has a maximum operating frequency of 300 MHz, but device vendors can tweak this setting to save on power. Nvidia provides less information on the Tegra 2 than it does for its desktop GPUs, so it’s best to move on to benchmarks. As in our iPad 2 review, we're turning to GLBenchmark 2.0.

In terms of frames rendered in a set period of time, the Xoom, Iconia A500, and Transformer offer more performance than the original iPad. But all three Tegra 2-based tablets still fall short of the iPad 2. Interestingly, the Transformer performs worse than the A500 with Honeycomb 3.1. Once we update to 3.2, Asus' tablet jumps ahead by more than 20%.

There is a direct relationship between memory bandwidth and triangle rates in the A4 and A5's PowerVR GPUs, due to their tile-based deferred rendering architecture. But PowerVR GPUs operate differently than what we're used to seeing on the desktop. Tegra 2, on the other hand, employs a more traditional z-buffered rendering architecture. As such, it's only possible to compare the triangle rates of competing Tegra 2-based tablets.

If you want to go into more depth than what is provided here, the full results of GLBenchmark 2.0 have been posted on Google Docs.

  • americanherosandwich
    If only some of them sold for $99... but a chance to win one of four for free = just plain awesomeness!
    Reply
  • compton
    Having recently tried the Transformer in person, I can say that it doesn't feel cheap and the novelty of the docking system could be awesome in future iterations. But as I recently found out with my $99 HP TouchPad, tablets have a long way to go in some areas. In the TouchPad's case, many of it's problems seem to go away when overclocking it's processor from 1.2Ghz to 1.8Ghz +. Of course, it's battery life is already less than compelling so you don't really notice the higher power usage. Like so much in life, better and faster hardware makes all the difference. Higher clock speed overcomes many of the problems HP could have ironed out had they given WebOS more time.

    The Transformer is a not-insignificant step forward for Android tablets. As an optimist, I believe the next iteration will be pretty damn good. But like the TouchPad, who knows how much longer it's going to be around?
    Reply
  • Dangerous Beans
    americanherosandwichIf only some of them sold for $99... but a chance to win one of four for free = just plain awesomeness!
    Yeah, if you are American. Hey Toms, how about you find some way to only display the comp if the reader is on an American IP address.
    Or better yet, find a way to let us enter.

    What is the point of a 32gb model when the tablets has a micro sd slot? I can get 2 32gb mSD cards for the extra $100 bucks.
    Reply
  • clonazepam
    I went to the verizon store to get help choosing some decent headphones for my bionic. While I waited for him to go in the back of the store and get a few models, I started playing pinball on the galaxy tab 10.1. When he came back there was that brief moment I couldn't decide to keep playing and ignore him, or set it down. win win here.
    Reply
  • clonazepam
    Dangerous BeansYeah, if you are American. Hey Toms, how about you find some way to only display the comp if the reader is on an American IP address. Or better yet, find a way to let us enter. What is the point of a 32gb model when the tablets has a micro sd slot? I can get 2 32gb mSD cards for the extra $100 bucks.
    They could do international possibly, if any international persons agreed to help pay shipping (I bet). A UK site I won't name allows international entries and lets them know up front they'd try to work with you on the shipping costs, etc.

    Wanted to add. I bought a transformer and dock for my mother. She's in her 60s and loves it. She takes it to work, to the coffee shop. I set it up for her, my first time with Android, and it definitely has its uses.
    Reply
  • Geef
    Well the first thing I think of when I'm looking at a tablet is NOT watching a movie in the park or playing around like most commercials show. I actually think of when I get up off the computer chair to head to the toilet. I don't read the newspaper here so where else am I gonna get my up to date info? Only bad thing I can think of for that is needing to wash hands and Tablet. :P
    Reply
  • ps3hacker12
    BTW WARNING ITS A US ONLY COMPETITION : (
    Reply
  • siege_templar
    i am so sad, i cant enter comp due to:
    under 18
    and i live in aus :(
    isnt tomshardware from germany?
    Reply
  • anonme
    On the other side of the screen argument it seems to be one of the few that does not need closed curtains.
    Heavens forbid, it sounds decent outdoors too thoug OLED is probably better.
    Reply
  • anonme
    On the other side of the screen argument it seems to be one of the few that does not need closed curtains.
    Heavens forbid, it sounds decent outdoors too thoug OLED is probably better.
    Reply