The iPad and its Performance

Apple knows how to make things feel fast. It’s all about making animations as smooth as possible and making sure that the UI always responds consistently. Apple isn’t perfect in this regard, but it does pay more attention to detail here than most other companies.

On the iPhone, scrolling is always smooth, swiping between home pages feels quick, apps launching are always well animated. The same is (mostly) true for the iPad, but thanks to a faster processor, many of these animations are physically faster. Bringing up the home screen is lightning quick, as is swiping between them. Scrolling is also very smooth, so much in fact that I found myself scrolling through emails and pages just because the animation was done very well.

There are some rough edges of course. While swiping between home screens is nice and fast, bringing up the quick search screen is choppy (not Android choppy, but choppy for the iPhone OS). The same is true for some other apps, particularly 3rd party ones. The latter point makes sense given that developers haven’t had much time with the device, but Apple not ensuring a perfectly smooth UI across the entire OS is telling.

Apple tends to move engineering resources around the company. The iPhone launch delayed the OS X launch that same year. And the iPad launch surely had some impact on other products. Or is it the other way around? Later this week we’ll see Apple preview version 4 of the iPhone OS, which implies a release sometime in the coming months (June?). An on-track iPhone OS 4 release could explain some rough edges with the shipping iPad, as well as why we don’t seem to have a plethora of amazing apps from Apple at launch.

Despite my nitpicking, this thing is definitely faster than the iPhone 3GS and even the Google Nexus One. Surfing the web, loading applications or generally just interacting with the device. Going to a 3GS from a Nexus One feels slow, going to a 3GS after using the iPad just feels wrong.

But with a larger screen you get the desire to want to do more and expect more from the iPad. I would say that in this sense the performance is a letdown. The A4 is speedy but not quite fast enough for this size of device.

  iPad (Apple A4) Google Nexus One (Qualcomm QSD8250) iPhone 3GS (ARM Cortex A8) iPhone 3G (ARM11)
Manufacturing Process 45nm 65nm 65nm 90nm
Architecture In-Order In-Order In-Order In-Order
Issue Width 2-issue 2-issue 2-issue 1-issue
Pipeline Depth ??-stage ??-stage 13-stage 8-stage
Clock Speed 1GHz 1GHz 600MHz 412MHz
L1 Cache Size ?? ?? 32KB I-Cache + 32KB D-Cache 16KB I-Cache + 16KB D-Cache
L2 Cache Size ?? ?? 256KB N/A
GPU PowerVR SGX Adreno 200 PowerVR SGX PowerVR MBX

To figure out where the iPad falls in the grand scheme of things I ran a number of web page load tests and browser benchmarks. To remove the internet from the equation, I loaded all pages off of a server on my own network. This is as close to a pure CPU and OS/browser benchmark as we’ll get.

Given that the iPad runs off smartphone hardware, the obvious comparisons are the iPhone 3GS and Google’s Nexus One. The former is based on a 600MHz Cortex A8, while the latter uses Qualcomm’s 1GHz Snapdragon QSD8250 running Android. Oh and there’s just one more thing:

This is ASUS' Eee PC 1001P. Priced below $300 it is the epitome of the netbook. Low cost and functional, but without looking overly cheap. Based on Intel’s Atom N450 processor this should put things in perspective. I ran the same set of benchmarks on it that I ran on the rest of the platforms. I used Chrome running on Windows 7.

  Apple iPhone 3GS Google Nexus One Apple iPad ASUS Eee PC 1001P
AnandTech Front Page 4.5s 4.3s 3.1s 1.2s
CNN Front Page 5.4s 4.4s 3.9s 2.8s
CNN Front Page 3 8.7s 6.8s 6.3s 3.5s
Facebook 2.5s 2.4s 2.0s 1.4s
MSN 10.5s 5.1s 5.0s 2.8s
Yahoo! 1.9s 1.6s 1.4s 0.8s
Engadget 15.0s 11.6s 11.1s 4.8s

To make this data easier to read I averaged all of the numbers for each device, normalized them to the iPhone 3GS (in terms of % faster) and put the data in a graph:

And now you see why I said the A4 does well against smartphones, but doesn’t cut it for the screen size of the iPad. While the iPad is 46% faster than the iPhone 3GS and 14% faster than the Nexus One on average, the Eee PC is 87% faster than the iPad. It is noticeable!

Real world JavaScript performance is also no contest between the A4 and Intel's Atom:

If Apple doesn't have plans to use Moorestown (or a derivitive) in its iPad at some point, I would be sorely disappointed in the company's ability to make intelligent hardware decisions.

I will give Apple credit, the iPad feels quick in most cases, which is probably why the sacrifice to go with a lowly Cortex A8 was made. However, when it comes to browsing the web, there’s a tradeoff. It’s much better reading web pages on the iPad, but it’s much faster on the Eee PC.

The comparison gets more complex when you look at things like application launch times. It takes the iPad 3 seconds to launch Pages, and less than 1 to launch Safari. If the application was previously in memory, the Eee PC can fire up Chrome in less than a second, otherwise it takes longer depending on what Windows decides to do with the disk at that moment. And launching Word from scratch takes much longer than 3 seconds.

Apple is relying on solid state storage and a very lightweight OS while netbooks usually have terribly slow hard drives and a bulky software stack. It’s a ginormous tradeoff. Web pages load quicker on a netbook, but are easier to read/navigate on the iPad.

What Apple absolutely needs in here is an Atom CPU. Apple buys itself a lot of leeway by using a very lightweight OS, but when a web page still takes a dozen seconds to load - you feel the pain. While I realize that Atom hasn't been suited for such an application until now, there's no reason Apple should've picked the A4 over Moorestown. Moorestown can fit in devices far smaller than the iPad, and would make this thing perform more like (and better than in some cases thanks to the OS) a netbook. I laughed when Jobs said that netbooks don't do anything well. While I'd agree a lot of the time, here they do seem to load web pages faster than the iPad.

The Silicon - Meet the A4 Honest Apple: Battery Life
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  • softdrinkviking - Thursday, April 8, 2010 - link

    it occurs to me that i would want a way to protect the screen from getting scratched, and that would mean a
    cover or case that would take the place of the clamshell design of a netbook/notebook.
    why would i want to pay a price premium for a device with slower performance which only achieves acceptable functionality with the addition of expensive peripherals?
    even after all the peripherals, i still lose the ability to effortlessly prop-up a netbook on my lap and type an email, or set a netbook up on a table in a coffee shop.
    nothing about the tablet form factor is convenient for on-the-go usage for me.

    the only situation where i can possibly imagine this being a preferable form factor is for wall mount usage or some other kind of "always left out in the open" type of use, like a universal remote control, or a mini home television viewer in the kitchen.
    but it seems too expensive for those uses to me.
    there must be a better alternative.
  • MacTheSpoon - Thursday, April 8, 2010 - link

    Thanks for the great review. I was shocked you'd typed 40% of it with the iPad.

    Would you mind doing a comparison between the iPad keyboard and a physical keyboard? Since there is no utility to measure WPM for the iPad, maybe you could time how long it takes to type the same passage on both--something with some semicolons, quotation marks, and/or em dashes would be ideal, as I'm curious how the virtual keyboard stands up when the user must switch between layouts.
  • Brian Klug - Thursday, April 8, 2010 - link

    You know, this was something I was dying to address a few times. I'm hoping that the iTextspeed application developers update their code soon to be iPad compatible, because that's something I want to test for sure.

    I've gotten to the point where I can touch type in landscape pretty easy, but I can also type pretty fast on the iPhone (around 80 WPM using their application). If and when it's updated, we might do something and include the update.

    If it helps any, this was also composed pretty quickly from an iPad. ;)

    Cheers,
    Brian Klug
  • solipsism - Thursday, April 8, 2010 - link

    1) How did you get a 720p video on the iPhone for the video test when the allowable maximum "up to 1.5 Mbps, 640 by 480 pixels, 30 frames per second" video?

    2) From my testing, the iPad uses about 20MB more than the 3GS on startup. Most, if not all, of this is for the GPU. I've also noticed that native apps are also using more RAM. While the 3GS has enough to support standard multitasking the iPad does not. Even switching pages in Safari on the iPad would have to be reloaded while the 3GS does not. This will even more of an issue with the 3G version of the iPad. This gives me doubts about multitasking unles iPhone OS v4.0 is much more efficient (making 3.2.2 a stand in, which looks to be the case) and Apple has a more intuitive quasi-multitasking concept to unveil today.
  • Brian Klug - Thursday, April 8, 2010 - link

    I can't speak about the RAM usage - are you using iStat or similar?

    However 720P H.264 video is certainly supported, which is what we used. I tested all the different profiles in handbrake, all of them work if you keep the video at or under 1280x720:

    "H.264 video up to 720p, 30 frames per second, Main Profile level 3.1 with AAC-LC audio up to 160 Kbps, 48kHz, stereo audio in .m4v, .mp4, and .mov file formats; MPEG-4 video, up to 2.5 Mbps, 640 by 480 pixels, 30 frames per second, Simple Profile with AAC-LC audio up to 160 Kbps, 48kHz, stereo audio in .m4v, .mp4, and .mov file formats; Motion JPEG (M-JPEG) up to 35 Mbps, 1280 by 720 pixels, 30 frames per second, audio in ulaw, PCM stereo audio in .avi file format"

    That's straight from http://www.apple.com/ipad/specs/

    I think you're getting confused with the MPEG4 limitation which is indeed 640x480. ;)

    -Brian Klug
  • Ph00 - Thursday, April 8, 2010 - link

    sorry to be ot but is that a black mouth cur dog?
  • Griswold - Thursday, April 8, 2010 - link

    I'll wait for iPad v2 with reliably working wifi, no overheating, working PDF export, at least a backside camera for snapshots and maybe short flicks and perhaps multitasking. Ill stop here because any more missing features would seem greedy - apple needs a reason to sell you the 2012 iPad...

    As for atom based ipad - are you nuts? Nobody wants that garbage. Gimme a dual core cortex A9 instead.
  • Mike1111 - Thursday, April 8, 2010 - link

    You mean the 2011 iPad, right? Because there's no way Apple isn't gonna do a yearly refresh cycle like they do with all their iPhone OS based products.
  • Mike1111 - Thursday, April 8, 2010 - link

    My mistake. You meant even iPad v2 in 2011 won't be feature complete because Apple needs some features for the 2012 iPad v3.

    Hm, how do I delete a post?
  • Lemonjellow - Thursday, April 8, 2010 - link

    "Sure, but so could a TV that made me pancakes. Neither is ready yet or guaranteed."

    Can you confirm or deny that someone is working on said TV project? :- D

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