The iPad 3 and Moore’s Law

At first sight the new iPad 3 seems to be a vindication of Moore’s Law. Apple wanted to significantly increase the pixel density of the screen, and had to wait until the components were cheap enough to sell the iPad for its usual price. Now, apparently, that wait has ended and the iPad 3 with Retina is here.

Still, not all is well with the iPad 3. Put simply, what Apple forgot here (or deliberately decided to overlook) is that Moore’s Law doesn’t go for data connections; especially not for mobile ones. Increasing a wireless data network’s speed doesn’t really depend on cheaper hardware: it’s a matter of bandwidth, frequencies, and more cell towers.

In order to display properly on the iPad 3, all graphics of both web apps and native apps must be doubled in pixel density, which means their size roughly quadruples. Clever compression will solve part of that problem, but not nearly enough.

The Next Web calculates that a more-or-less random app, Consume, will go from an 18M to a 35M download, solely because of the enhanced graphics that are needed for the Retina screen. Besides, the app is now well above Apple’s 20M limit for downloads over the mobile network.

People who want to enjoy their Retina display will thus be forced to download the app over wifi. That’s perfectly possible, but even then the wait time is roughly doubled, which is not good for today’s consumer who wants everything to happen instantly.

Update: It seems Apple has increased the limit to 50Mb. That doesn't solve the fundamental problem, though.

The problem is even worse with the mobile web. Jason Grigsby delved into the way Apple itself serves Retina-optimised images to its new iPad site. Essentially, they download the normal images first, and if a check for the iPad 3 is positive it then downloads the optimised images.

The image of the iPad itself is 117K in the normal version and 351K in the Retina version. Both versions are loaded to the iPad.

Now the dual download is not necessary; no doubt some clever use of conditional image loading techniques will allow consumers to skip the 117K download. That still leaves them with the 351K download, though.

More in general, some web developers will start to serve Retina-optimised images pretty soon, jumping on the Apple-induced bandwagon. In the end this is not good for the web, because it’s just too bloody much data. Over a mobile connection this is a disaster waiting to happen. Over a wifi connection the damage is more limited, but it will still take you roughly 2 to 3 times more time to load a Retina-optimised site than a normal site.

Thus the Retina display puts incredible extra strain on the already-strained mobile web. Retina may be great for the end user, but the data networks simply cannot handle it (yet). Thus it’s either way ahead of its time, or it’s a dud. We’ll figure out which in the next year or so.

So be very careful in including Retina-optimised graphics on your site. It means the end user has to wait longer for a site to load, and that goes contrary to the current trend of faster, faster, faster.

I’m very afraid that exactly because of its excellence the Retina display will be a severe set-back for the mobile web, and maybe also for native iOS apps. Apple shouldn’t have ignored the fact that Moore’s Law doesn’t go for data connections.

This is the blog of Peter-Paul Koch, web developer, consultant, and trainer. You can also follow him on Twitter or Mastodon.
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