Fresh out the frying pan and into the fire, I just finished my Nexus One review late last night only to have my iPad preorder show up early this afternoon. I had been preparing for it's arrival not by downloading apps but by figuring out what comparative benchmarks I wanted to run on the iPhone 3GS and Nexus One.

As the first device to use Apple's A4 SoC I wanted to see how it stacked up against the Cortex A8 and Qualcomm's QSD8250. All three chips appear to be dual issue in order architectures with varying pipeline depths, clock speeds and cache sizes.

At 600MHz the Cortex A8 in the iPhone 3GS is the slowest out of the bunch. The Snapdragon is much faster as we just established thanks in part to it's 1GHz clock speed. But what about Apple's 1GHz A4?

There's very little we know about the A4 other than it's operating frequency. It is manufactured by Samsung but on an unknown process node. Jon Stokes recently stated that Apple's secrecy surrounding the chip is because it isn't anything special, just a Cortex A8. If that is true, I suspect that it would have to be manufactured at 45nm in order to reach such a high clock speed.

With a new silicon mask there's also the chance that Apple moved to LPDDR2 to boost memory bandwidth; a change that most SoC makers are planning to make this year.

So how does Apple's A4 stack up against today's favorite smartphone brainchild? Keep in mind that these results are generated by running two different OSes (Android 2.1 and iPhone OS 3.2) and two different browsers. What we're looking at is the performance delivered by the combination of the CPU and the software stack:

Applications Processor Performance
  Apple iPad (Apple A4) Apple iPhone 3GS (ARM Cortex A8) Google Nexus One (Qualcomm Snapdragon QSD8250) % A4 Faster than Snapdragon
Load www.anandtech.com 6.2 seconds 9.3 seconds 8.8 seconds 41%
Load www.digg.com 10.6 seconds 18.0 seconds 11.5 seconds 8.7%
Load www.tomshardware.com 7.9 seconds 13.9 seconds 8.6 seconds 8.7%
Load www.arstechnica.com 7.8 seconds 13.8 seconds 11.0 seconds 39.9%
Load www.legitreviews.com 6.8 seconds 12.3 seconds 8.6 seconds 26%
Load www.techreport.com 3.7 seconds 7.4 seconds 4.2 seconds 11.6%
Load www.engadget.com 13.8 seconds 22.8 seconds 22.0 seconds 59.4%
Load www.gizmodo.com 14.1 seconds 21.4 seconds 16.7 seconds 18.5%
Load m.cnn.com 3.0 seconds 6.0 seconds 2.6 seconds -11.8%

Unless otherwise specified, I loaded the full version of all of the websites above (the exception being CNN, where I used the mobile site). To ensure reliability, I ran all of these tests at least 5 times, threw out any outliers and averaged the rest. The rests were also run at around the same time to ensure that content on the sites was as similar as possible (and thus shouldn't be compared to this morning's Nexus One results). You'll note that the Engadget results are a bit odd. It looks like the iPhone and Nexus One scores are bottlenecked somewhere else (there seemed to be some network issue plaguing the loads, but it wasn't present on the iPad), but if you toss out the very large differences you end up with what I believe to be the real story here. Update: Flash wasn't enabled on any device (not supported on iPad/iPhone, not officially available on Android yet), and all three devices connected to the same WiFi network.  The Apple devices used mobile Safari, while the Android device used the Android Browser.  Both are WebKit based but there are obvious, unavoidable software differences.

Removing the AnandTech, Ars Technica and Engadget loads (which were repeatable, but unusually long) the iPad loads web pages 10% faster than the Nexus One. If you include those three results the advantage grows to 22.5%. I'd say somewhere in the 10% range is probably realistic for how much faster the A4 is compared to the Snapdragon.

I also ran the official WebKit SunSpider JavaScript Benchmark on all three platforms to give us a network independent look at real world JavaScript performance:

If we take the network out of the equation, the A4 in the iPad has a 37.6% performance advantage over the Qualcomm QSD8250. This actually supports some of the larger performance differences we saw earlier. If Apple can manage to deliver this sort of performance in its smartphone version of the A4, we're in for a treat.

The why is much more difficult to ascertain. It could be as simple as the the iPad OS being better optimized than Android, a definite possibility given how much longer Apple has been working on it compared to Google. The advantage could also be hardware. The A4 may boast higher IPC than Qualcomm's Snapdragon thanks to better core architecture, larger caches or a faster memory bus. The likely case is somewhere in between, where the iPad's advantage comes from a combination of hardware and software.

It could also be a power optimization thing. The A4 in the iPad is paired with a much larger battery than the QSD8250 in the Nexus One, Apple may be able to run the SoC at more aggressive performance settings since it doesn't have to worry about battery life as much. Either way the one thing we can be sure of is Apple's A4 SoC is much more like a 1GHz Cortex A8 rather than anything more exotic. Good work Jon :)

I should note that while the performance improvement is significant, it's not earth shattering. Despite the early reports of the iPad being blazingly fast, I found it just "acceptable" in my limited time with it thus far. I'll go into greater detail in my full review later.

This does bode well for the upcoming 4th generation iPhone, which is widely expected to also use the Apple A4 SoC. That upgrade alone should put the next iPhone ahead of Google's Nexus One in performance, assuming that it offers the same performance as it does in the iPad. Pair it with a modernized and feature heavy iPhone OS 4.0 and we might see an Apple answer to Android in 2010.

The A4 is particularly exciting because it combines Snapdragon-like CPU performance with a PowerVR SGX GPU. A much better option than the aging ATI core used in Qualcomm's QSD8x50 series.

With Apple showing its A4 performance this early, Qualcomm also has a target to aim at. The first single-core 45nm Snapdragon SoC due out in 2010 will run at 1.3GHz. That could be enough to either equal or outperform Apple's A4 based on what we've seen here today.

Expect our full review of Apple's iPad as well as more discussion about the A4 next week. Have a great weekend guys.

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  • Brian Klug - Sunday, April 04, 2010 - link

    Wow, I have no idea what i was thinking yesterday, (1000-614)/614*100=62% ;)

    I failed at my arithmetic last night. Sorry guys ;)

    -Brian
    Reply
  • duda - Sunday, April 04, 2010 - link

    This is the biggest fail on an article I have read in a long time. In fact I registered just so I could point out why this is sooo bad. The writer is probably some Apple douche noob.

    You are trying to compare PROCESSORS, yet you end up testing the web-page loading speed of two completely different devices. Geez - absolutely inconclusive!! There are so many things wrong with this article I don't know where to start.

    Ok, Analysis 101:

    If you are going to compare two things, and two things only (in your case the Apple A4 Processor, and the Snapdragon Processor). Then you have to make sure that any other variable factors are either eliminated or minimised. If you don't your results and measurements may be influenced by something you are not testing (in your case, the whole rest of the hardware and software of the devices!)

    You are comparing a Google Nexus One to an Apple iPad, the two devices are completely different. You can't say you are comparing the processor of the devices when there are sooo many other variable factors involved in taking your measurements, such as the networking and graphics hardware. You really don't think the Processor does everything do you??

    Secondly, you are not even measuring output and functionality in the processors, you are measuring how fast web-pages load.

    What this article should really be saying is, "How does the Apple iPad match up with the Google Nexus One on Webpage loading times?"

    There you go dumb a..

    Have a good Easter :)
    Reply
  • Screammit - Sunday, April 04, 2010 - link

    Holy not-getting-the-point, batman!

    I'm going to save some time and energy and direct you to DevilSmurf's post, on or around page 4 of the comments, that person stated it better than I ever could.
    Reply
  • tushaar - Sunday, April 04, 2010 - link

    As you said, the better performance might be because of the larger battery and this might mean that the A4 in the new iPhone might NOT surpass the Nexus One. Reply
  • Chloiber - Sunday, April 04, 2010 - link

    This would be the same if you said:

    500Mhz to 1000Mhz is an increase of 50% in clock speed. Obviously that's wrong - it's double or 100%. 1000Mhz -> 500Mhz != 500Mhz -> 1000Mhz
    Reply
  • vigg0 - Sunday, April 04, 2010 - link

    The soon to be released Samsung Galaxy S has a 1 Ghz Cortex A8 combined with a PowerVR SGX540. Given the fact that Samsung is producing the A4 SoC for Apple, could it be so that iPad/Galaxy use the same hardware? Reply
  • LyCannon - Sunday, April 04, 2010 - link

    Now, from what I have read, the iPad is supposed be be a replacement for a netbook. If that's the case, why the heck are you comparing it against a smartphone? Shouldn't you compare it against other touch-based netbooks in the same price range? Reply
  • misterPaul - Sunday, April 04, 2010 - link

    A lot of other sites are linking to this article as a review of the iPad's CPU. Reading the defensive comments here it's obvious that this is more a comparison of the CPU expected to be used in the 4 gen iPhone.

    The fact is there's a lot of hate for this tablet and Apple in general at the moment. Don't ask me why, I guess it's what they represent - tightening up control of hardware. Anyway, the fact is this isn't a review of the iPad, as the iPad isn't a smartphone and doesn't really share many characteristics with them (except the poor hardware and limited user input methods).
    Reply
  • yacoub - Sunday, April 04, 2010 - link

    Your numbers are calculated the way a marketer would do them (% faster), instead of the real world / conservative method that most folks would appreciate (% improvement, or the difference in the amount of time from start to finish between the two devices).

    For example, the first benchmark you state 6.2 vs 8.8 is "41% faster", yet in reality the improvement seen over the other device is 29.54%, because the iPad at 6.2s takes roughly 70% of the time the Snapdragon takes at 8.8s. The correct formula is ((6.2 / 8.8) * 100) -100
    It's taking ~70% of the time that the Snapdragon takes to load Anandtech.com.

    I know, I know, the way you're doing it is also "right" in a strictly mathematical sense, but it's a math trick used by marketers to be able to post higher numbers, but it rubs the wrong way for a technical review site to be doing that.

    Here are the correct numbers for each site load, and as we see, the bigger the difference between the two devices' scores, the more pronounced the exaggeration in the marketing numbers, which is why they like to calculate that way (% faster) instead of what matters more (% improvement):

    A4 percentage improvement over Snapdragon:
    29.54%
    7.8%
    8.14%
    29.09%
    20.93%
    11.9% (you actually got pretty close on this one (TechReport). Using the incorrect/marketing calculations you used with other sites, i think this one should have been 13.5%?)
    37.27%
    15.57%
    -15.38% (m.cnn.com is still slower on the A4, as noted)
    Reply
  • Anand Lal Shimpi - Sunday, April 04, 2010 - link

    I did it for consistency with previous performance testing in smartphone reviews (I started out doing it the way you're describing).

    The % reduction in time and % faster are both valid ways of expressing the data here. Folks usually like to know the latter in my experience, but if the overall demand is for the former I've got no problems switching :)

    Take care,
    Anand
    Reply

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