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April 04, 2010


Any machine that runs JavaScript faster than an iPad will also consume batteries that much faster. And that is a competitive disadvantage.

I feel pretty confident that iPhone OS 4 will bring a speed improvement to Safari's JavaScript engine.

Just sayin


So poor JavaScript performance is a... competitive advantage? Dude, the RDF is strong with you.


I sure hope so! :-)


And have you noticed this to be an actual problem, in practice, or are you just obsessing over benchmarks?

With Html5 javascript is no longer required. Please look at nojax264 standard. As mentioned above it also helps with battery life. And it crashes constantly, besides being aesthetically sub-par. BTW IE9 will no support it either.

I'm presuming that's Safari on the MBP. I wonder how Chrome fares since it's allegedly faster?

(Though I don't know what standard the Mac builds are at, since I don't have a Mac)

htc incredible with several apps running at the same time. browser running flash lite.


"But JavaScript performance like this effectively means the iPad can't run complex JavaScript apps either. "

This statement is FUD.

While I don't dispute a full laptop will be faster than a mobile chip on a synthetic benchmark, I am wondering what real-world website you don't feel you can run on the iPad due to slower JS performance. Examples?

Heavy ajax sites like gmail run quite well on the iPad. Yes, I have an iPad and use it for such sites everyday (including for writing this post).

And in other news... Bicycles report slower times in quarter mile tests than new Tesla sports car. This effectively means bicycles cannot be relied upon for transportation.


It's not FUD but you're right, I should have cited examples. It's really heavy-JS apps like http://almost.at and other Cappuccino apps (like our very own http://spanningbackup.com/) that really show the problem.

I understand that iPads aren't supposed to be laptop replacements (BTW I *love* mine) but they should be able to run web apps at least as well as junky netbooks.


If this was just informational, the post would be stronger, but it's stated although this is a bad thing.

As Glenn Rempe pointed out very well, you ride a bike for certain reasons and you drive a sports car for others. To expect the same things out of either would be shortsighted at best.

An iPad does what an iPad should do extremely well. If a laptop could not significantly best it's performance, I would fear for the longevity of that laptop's maker.

After my last reply decided to run across 5 browsers, results (fastest to slowest):

Safari Nightly (Webkit) 4.0.5 (6531.22.7, r58691): 311.4ms
Chrome 5.0.375.29: 328.2ms
Safari 4.0.5 (6531.22.7): 371.2ms
Opera 10.50 pre-alpha (8166): 416.6ms
Firefox 3.6 (20100115): 949.8ms

Looks like the webkit nightly updates are edging out Chrome's most recent release. Firefox, as expected, is dead last however I wouldn't have expected it to be more than twice as slow as Opera.


"It's really heavy-JS apps like http://almost.at and other Cappuccino apps (like our very own http://spanningbackup.com/) that really show the problem."

I love Cappuccino, and SproutCore, and I applaud the direction they (and you) are going with true web applications that are closer to desktop feel and functionality.

That being said I hate to break it to you though that the http://almost.at site feels pretty sluggish even on my desktop Mac (2.3Ghz Core2 Duo) running the latest Chrome dev channel build. It takes ~10 seconds to page load even when cached. So I'm not sure why you would expect an app which struggles to some degree on the desktop to perform at anything but a sub-par level on an ARM chip mobile device that is severely constrained on CPU and RAM. Perhaps there is still some optimization to be done within Cappuccino (which is still in Beta) or your apps implementation with it.

The comparison to 'junky netbooks', which run primarily the Atom chip is not really valid either IMHO. Apple, and its buyers, made conscious engineering decisions to use a custom ARM chip which strikes a balance in favor of sipping energy instead of pure performance which results in the real world 10+ hours of video playback for instance. This is a tradeoff of horsepower in the energy sense of the word and the reason that no smartphone platforms are using Atom chips. At this moment in time there are few JavaScript apps which truly push the limits as yours does. I would not trade my excellent all day battery life for faster performance in benchmarks or the few sites that can truly tax the device. My device still feels quite snappy on the vast majority of websites, even those that are considered javascript heavy by todays standards (e.g. GMail).

Personally, I'm still wondering what you were trying to accomplish with this article.


PS - The new SproutCore touch library which was just released performs terrifically on the iPad if the demos are representative of real world apps. In addition they have the benefit of being designed to work in a touch environment which Cappuccino is currently not optimized for from a UI interaction perspective.

See : http://bit.ly/b8gZ5z

The thing is that Apple knows that only 5% of the market cares. The tinkerers, and true tech geeks might be turned off by the slow performance, but the vast majority of everybody is happy if it looks nice in their living room.


For day to day web browsing - isn't the iPad showing that the time to download is usually > time to render? That you're more likely to feel lag because the page is still downloading, than it's downloaded, but you're waiting for it to render?

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