Is AT&T Capping Upload Speeds?

It recently came to PCMag's attention that AT&T may be capping upload speeds on many devices—to speeds far lower than its network can support. This may be the case for many devices on AT&T other than the iPhone 4.

We saw evidence of this recently when testing AT&T's latest round of USB modems, the USBConnect Shockwave 4G and the USBConnect Adrenaline. In many parts of NYC, both devices showed upload speeds far below their capabilities. It seems that AT&T devices that should support HSUPA (which should enable uploads up to 1Mbps, according to our past modem tests) are being limited to UMTS (maxing out at 384kbps), which is less than half that speed.

Originally alerted by reader Zack Nebbaki, we ran some head-to-head tests in the PCMag Labs to see just how the numbers stacked up.

We tested an HTC Inspire 4G, a Motorola Atrix, and an Apple iPhone 4. The Inspire and the Atrix are supposed to be faster than the iPhone overall, as both devices use HSPA+ 14.4 modems while the iPhone has an HSPA 7.2 modem.

We used Ookla's SpeedTest app and connected each phone to the same server, then ran the test six times. As you can see in the chart below, we got UMTS (not HSUPA) upload speeds on the Inspire 4G and the Atrix each time. Tests done with the iPhone 4 at the same time, in the same location, showed dramatically higher upload speeds. This correlates with our results for the two USB modems we tested recently.

These results suggest that AT&T is, in fact, capping upload speeds for at least several different non-iPhone 4 devices. Now, we haven't worked out the variables here. This could be a problem specifically with the four devices we've tested (the two phones plus the Adrenaline and Shockwave USB modems), or a problem that specifically only affects certain parts of New York City.

We contacted AT&T and asked if it is capping upload speeds to UMTS levels, and if so, where this is being done and for how long. We also asked why the iPhone is getting faster speeds than the other devices.

AT&T was evasive, saying, "As you noticed, we have a number of HSUPA devices today and we will have more HSUPA-enabled devices in the future—new devices and updates to existing models."

Please note that AT&T's comment does not appear to be a denial of anything in this article.

About Our Expert

Alex Colon

Executive Editor, Reviews

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I’m PCMag’s executive editor of reviews, steering our coverage to make sure we're testing the products you're interested in buying and telling you whether they're worth it. I've been here for more than 10 years. I previously managed the consumer electronics reviews team, and before that, I covered mobile, smart home, and wearable technology for PCMag and Gigaom.

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The other big screen in my life is a 65-inch LG C9 OLED TV. If you’re wondering whether OLED is worth the premium over LCD, I’m here to tell you that it is.

I’d be doing my beloved LG C9 a disservice if I didn’t have it hooked up to a capable sound system, so I have a Sonos Beam sitting on a media console underneath the TV, and two Sonos Ones set up as rear channels for surround sound. If you’re a Sonos user, I highly recommend adding the Sonos Sub to your setup. It’s definitely a little more expensive than it should be, but it's truly money well spent.

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With 15 years of experience in tech, Alex guides PCMag's product testing to help you decide what's worth buying and how to get the most out of it.

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