Update 9/28/2012: There is an important followup to this post, with new information about Apple's Podcasts app, Downcast's data and power consumption, and a bug in Safari's bookmark syncing.

I received my iPhone 5 late Tuesday night. It is without question the best phone I've ever used. Everything on it is fast, especially the 4G LTE, where I'm averaging about 30-40 Mbps down, which is faster than my home internet.

But that speed comes with a price: The iPhone 5 gobbles data. My iPhone 4 used, at most, 60 MB a day. I had few issues staying inside a 2GB data cap. But after one 10 hour day, my iPhone 5 had used 350 MB. At that rate, my current 4GB data cap will be burnt up in less than 12 days.

To find out what was using all the data, I used the $0.99 app DataMan to identify 3 main culprits:

iTunes Match

Apple's $25 a year music syncing service is advertised as a way to have your music anywhere, anytime. But its data usage is astronomical.

Just playing one song, Temple of the Dog's Hunger Strike, used a whopping 8 MB of data. That song is about 4 minutes long. To put things in perspective, it took about 20 minutes of listening to Pandora to use that much -- 5 times as long.

It doesn't help that in iOS 6, Apple took away the ability to see what's on your device and what's in the cloud. I guess the idea is to just play anything and not worry about it, which is fine as long as you're not dealing with a data cap.

If you do have a cap, make it a top priority to turn off iTunes Match's cellular data use. Open the Settings app, then go to Music, then scroll down until you see "Use Cellular Data" and turn it off.

Unfortunately, if you're not on Wi-Fi, any music not on your phone will be grayed out, so you'll probably also want to turn off "Show All Music."

I don't understand why they set iTunes Match up this way. Right now, it's an offer to spend $25 a year to hand over the rest of your bank account to wireless carriers. Why can't I make it hide my non-local music while on cellular internet? Why doesn't it compress my music before I stream it over 3/4G? Why doesn't it have separate tabs for local and cloud music, like Amazon's Cloud Player does?

Who knows? Maybe Apple employees get free unlimited data for life, because iTunes Match is definitely not designed for average cellular customers with data caps.

Flyover View in Maps

You know those fancy 3D city layouts? I loaded up Manhattan and the Apple campus in Cupertino. 16 MB gone in 1 minute flat. Avoid it unless you're on Wi-Fi.

Apple needs to add a Wi-Fi only switch for this feature. It's a glutton.

Apple's Podcasts App

Apple recently released their own Podcasts app, having taken that functionality out of the built-in Music app in iOS 6. I hadn't tried it until recently, because until last week, there was no option to only download new episodes over Wi-Fi.

I've been trying it out since then. It's not the best, but I had no major beefs with it until Macworld's Glenn Fleishman pointed out that regardless of settings, it was still downloading over cellular.

I had been using the app all day, with no apparent data usage. However, my usage had been creeping up all day for no apparent reason. Then, on my drive home, only using the Podcasts app and a couple of Siri requests, my usage shot up by 50 MB.

Siri does not use that much data. I deleted the app and the usage creep stopped.

If you enjoy podcasts, do yourself a favor and splurge on Downcast or Instacast. It'll save you money in the long run.


After taking these steps, I managed to keep my data usage at a "svelte" 150 MB. Now that I've deleted Apple's Podcasts app, I hope it'll be lower tomorrow.

For those of us with data caps, this is a nightmare, and one that I think will blow up in Apple's face when customers receive their bill.

I'm fairly light data user. I don't watch videos over the cell network. Most of my usage is browsing, social networking, messaging, and streaming audio. I can only imagine what that usage is going to be for heavier users who decide to try Netflix or FaceTime on 4G.

The iPhone, contrary to popular myth, used to be the most data efficient phone in its class. What happened?