The iPhone 8 is the fastest iPhone ever, although it doesn't quite match up to gigabit LTE phones—and you have to be careful about which model you get. Our testing shows that the iPhone 8 supports 600Mbps speeds on US and Canadian networks, much like the Essential Phone PH-1 does. It lacks the 4x4 MIMO antennas needed to extend speed and coverage on US networks to the levels seen on the Samsung Galaxy S8, however. But that's not quite the whole story.

Two iPhones, Maybe Three

There are three versions of the iPhone 8/Plus on sale around the world. One has a Qualcomm X16 modem and is sold as the unlocked US unit, or with Sprint, Verizon, and Australian carriers. The second, which we have not yet tested, is sold by AT&T, T-Mobile, and Canadian carriers. We are assuming that one has an Intel XMM7480 modem. There is also a Japanese version, only available in Japan.

We go into the difference between the two US iPhone models in our story Why You Should Buy an Unlocked or Verizon iPhone 8, iPhone X. To make a long story short, the Intel model lacks support for the CDMA system that Sprint and Verizon use, and may have weaker performance overall.

We took a look inside the Qualcomm iPhone with the help of Ookla's Milan Milanovic. (Note: Ookla is owned by Ziff Davis, PCMag.com's parent company.) Milanovic has a key piece of equipment we don't have in-house, provided by Rohde & Schwarz. Along with its invaluable engineering support, Rohde & Schwarz supplied CMWflexx test equipment consisting of two R&S CMW500s, one R&S CMWC controller, and a TS7124 RF Shielded Box equipped with four Vivaldi antennas for up to 4×4 MIMO, ensuring high reproducibility of OTA MIMO measurements.

We also tapped into Ookla's Speedtest Intelligence database to look at crowdsourced reports from the first weekend of iPhone 8 usage, comparing it with earlier iPhone models on the same wireless carriers. The results there are very preliminary, but look good for the new iPhones.

The iPhone 8 and the iPhone 8 Plus were even less of a change from the 7/7 Plus; they probably shoul

800Mbps, but Only in Australia

The iPhone 8 is missing one of the components needed for gigabit LTE, or LTE category 16, in the US. The Qualcomm X16 modem can do Category 16, as we've seen on the Galaxy S8 and Moto Z2 Force. The phone supports 256QAM encoding and 4x carrier aggregation to 80MHz of spectrum, but not 4x4 MIMO antennas, which would improve both speed and signal strength. In theory, that would make this an 800Mbps phone, also known as LTE category 15.

The lack of 4x4 MIMO is probably why the iPhone still falls short of the Galaxy S8 when it comes to recovering from dead zones, a notorious iPhone problem. We took an iPhone 8 and Galaxy S8 on the New York City subway, where they dropped in and out of T-Mobile coverage. The Galaxy S8 recovered faster in 8 out of 11 tests, and where it did, it was an average of 16 seconds faster than the iPhone at regaining LTE signal; when the iPhone won, it did so by 5 seconds on average.

The phone only supports 60MHz of aggregation on bands that matter to Americans and Canadians. While Canada has 75MHz, 4x carrier aggregation up and running with Bell and Telus, the phone doesn't support the 2/4/7/7 setup that they use, limiting the iPhone's speed on those carriers. In Canada, it's a 600Mbps phone, or LTE category 12.

No US carrier uses more than 60MHz of carrier aggregation right now, relying on 4x4 MIMO to reach their best speeds, which the iPhone does not support. That means this is a 600Mbps phone in the US as well.

You may need to go to Australia to get full speed from the iPhone 8, as the phone does support the 80MHz, band 1/3/7/28 carrier aggregation that Telstra uses. We've also heard the same may be true in Japan and China, although we don't know enough about their networks.

The Fastest iPhone Ever?

We also looked at Ookla Speedtest Intelligence data for iPhones from Sept. 22-25, 2017 on LTE connections, filtering for carriers with more than 100 unique devices running tests during that time. That's still a pretty low threshold, so we'll only take broad-stroke conclusions from that data.

The sample sizes here are small, but decent: 1,604 AT&T iPhone 8 Plus units as compared with more than 10,000 iPhone 8 units. Still, though, we'd like to test more in a month or so.

As evidenced in the chart below, we're seeing improved results on every US carrier between the iPhone 6, 7, and 8 generations. These charts are for the Plus-sized phones, but we're seeing the same trends for the regular phones as well. Also, notice how the Qualcomm phones are consistently slightly faster than the Intel ones.

We had some results from Bell in Canada and from the three Australian carriers, too. They also showed improvement from generation to generation, with a difference: on the Australian carriers, there was a dramatic leap from the iPhone 7 to the iPhone 8. For example, on Telstra, we saw average speeds increase from 64Mbps down with the iPhone 7 to 82Mbps down on the iPhone 8.

How About Coverage?

Whether you see better coverage on your new iPhone depends on how old an iPhone you're coming from and what carrier you're using. If you're on Sprint or T-Mobile coming from an iPhone 6 or earlier, you'll see dramatic improvements.

Both models of the iPhone 8 support all of the frequency bands used in the US and Canada except T-Mobile's new Band 71, which will extend rural coverage in the future. (So far, the LG V30 is the only phone with Band 71.) Neither phone, as far as we know, supports Sprint's HPUE system, which improves upload speeds in weak-signal areas.

If you're coming from a more recent iPhone, you won't see a dramatic coverage improvement. In the US right now, it would take 4x4 MIMO to eke out better performance in weak signal areas—and for that, you'll probably have to wait until 2018's iPhones, or get an Android phone.

For more on network speeds in the US, see our report on the Fastest Mobile Networks.

Further Reading

Mobile Phone Reviews