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 6.2 seconds 9.3 seconds 8.8 seconds 41%
Load 10.6 seconds 18.0 seconds 11.5 seconds 8.7%
Load 7.9 seconds 13.9 seconds 8.6 seconds 8.7%
Load 7.8 seconds 13.8 seconds 11.0 seconds 39.9%
Load 6.8 seconds 12.3 seconds 8.6 seconds 26%
Load 3.7 seconds 7.4 seconds 4.2 seconds 11.6%
Load 13.8 seconds 22.8 seconds 22.0 seconds 59.4%
Load 14.1 seconds 21.4 seconds 16.7 seconds 18.5%
Load 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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  • metafor - Sunday, April 4, 2010 - link

    NVM, found them:

    Droid's 550MHz A8 on Android 2.0 was significantly slower than the iPhone 3GS's 600MHz A8 running 3.1.2 of the iPhoneOS. What's interesting is that, since the N1's release, the browser has apparently gotten faster compared to the 3GS.

    Also, this doesn't take into account the rest of the SoC hardware.
  • Alexstarfire - Sunday, April 4, 2010 - link

    I took a look at that site and one of the charts is labeled incorrectly. If you take a look at the part where they show the average load times for the iPhone you see that with the except of 2-3 websites that all the phones are pretty equal. For 2 of the websites the iPhone is significantly slower, yet when you look right below that chart where they just look at the average load time over all the web pages you see that the iphone somehow comes out below the Droid. I did the calculations myself and based on the previous chart the iPhone should be the one loading in 9.3 seconds, not the droid.

    I don't which one they got wrong, but because of that you can't really use any of the results that are on that site.
  • metafor - Sunday, April 4, 2010 - link

    Arstechnica is a pretty reputable site. In either case, with data as sparse as it is, it's the closest source I can find. Added Droid data would be awesome using the same test setup used here.
  • Alexstarfire - Sunday, April 4, 2010 - link

    They might be, but that doesn't change the fact that something is simply WRONG. Without knowing which is which, in other words without them actually reviewing the data to make sure it's accurate, it's all useless.
  • Brian Klug - Sunday, April 4, 2010 - link

    You find the 60% increase not surprising? Since I generated those numbers, I have to disagree. Remember that the increase from 614 MHz to 1 GHz represents a roughly 30% increase in clock speed, but the JavaScript performance is double that at 60% better.

    I find that surprising. It's clear to me at least that there is much more at play here that we haven't uncovered yet. I pulled the user agents from both browsers and found that while they're running different versions of webkit (unsurprising), theyre not that different. It'll be interesting to see if the performance is architectural or software. Likely its some combination of the two.

    Brian Klug
  • misaki - Sunday, April 4, 2010 - link

    You can get results like this just from comparing different versions of webkit and google chrome on the same pc... They are constantly leapfrogging each other with every version bump.

    All this says is iPad is faster than the Nexus One, not how well the CPUs perform.
  • bsoft16384 - Sunday, April 4, 2010 - link

    My experience today (about 30 minutes with the iPad) was also that it was "acceptable" but not "fast".

    I'm not sure why everyone keeps calling the iPad "super fast". Yeah, it's faster than the iPhone 3GS, and it's a bit faster (looks like about 20%) than the Nexus One.

    Here's the problem: the Nexus One isn't exactly fast, and the 3GS, while fast for a phone, is positively anemic for a PC.

    When I used the iPad today, small sites (like Google) loaded plenty fast, but more complex sites like Engadget were pathetically slow. Engadget took around 25 seconds for me (possibly because it was loaded with huge images this afternoon), which is stupid. And, no, it wasn't the Internet connection, since the MacBooks at the same Apple store were very fast today (the Apple store in Boulder, CO has at least a 45Mbps dedicated connection from AT&T; I've benchmarked it before).

    In the days of dial-up, 256kbps DSL, and Pentium III CPUs, 15+ seconds to load a site might have been acceptable. But today even a moderate broadband connection (like my 12Mbps Comcast) and a moderate CPU (like the 2.53GHz Core 2 Duo in my ThinkPad) can load even big sites like Engadget in a couple of seconds.

    Oh, and by the way - my 2.53GHz Core 2 Duo T400 does the SunSpider benchmark in 351ms (latest Chrome beta). That's 29 times faster, or 11 times faster per clock. And that's with one core (I locked Chrome's affinity to CPU0 only; the JavaScript engine doesn't benefit much from the second core).
  • metafor - Sunday, April 4, 2010 - link

    True but that Core2 of yours is eating up ~20W. These SoCs, including the graphics engine, are taking up less than 1W.

    Also, the Pentium III at 1GHz would still be faster than these Cortex/Scorpion based CPU's. It was 3-issue (more if you worked the 1-1-3 rule) out-of-order processor.
  • 96redformula - Sunday, April 4, 2010 - link

    How are you going to compare Intel Atom Netbook vs iPad without having backround processes in windows(manufacturer installed software) affecting the Netbook. Are you going to do a clean install of Windows 7 on the netbook?

    I am asking this knowing well that many people are seeing poor performance on many of the netbooks due to bloated manufacturer software bogging down the Atom CPU. I.E. Lenovo S10-3t is a good example of one with lots of crud pre-installed bogging down the processor, people seem to be seeing big differences reinstalling the OS as there is so much preinstalled garbage running.
  • TemplarGR - Sunday, April 4, 2010 - link

    You are wrong, 600mhz to 1ghz is not 30% increase in speed, it is ~65%.

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