Google Pixel 6 Pro vs. Samsung Galaxy S21: Which One Wins At 5G?

Google's Pixel 6 Pro has several ground-breaking new components for the US, but the one Google least wants to talk about is its Samsung modem.

After many years of using Qualcomm's technologies to connect to 4G and 5G networks, Google seems to have switched over to Samsung to pair with its in-house Tensor processor—making the Pixel 6 Pro the only Samsung-powered 5G phone in the US.

"Hey, what about Samsung phones?" you ask. Samsung's US phones all use Qualcomm or MediaTek processors and modems rather than Samsung's own Exynos line. Phones outside the US more often use Exynos, including the flagship Galaxy S21 line. Here in the US, both Apple's iPhone 13 line and Samsung's S21 flagships use Qualcomm's X60 modem.

Connectivity is important in a connected device. If you can't stay connected, smartphones become pretty frustrating to use. So knowing whether a new component affects connectivity is pretty important. With that in mind, we set out for a weekend and took thousands of signal samples to divine the difference between devices.

We can't eliminate every variable here. A phone's network performance isn't just in its modem; antennas, power amplifiers, and software all play a part. But take enough samples, and some conclusions can become clear.

Mysteries of the Modem

The Pixel 6 Pro's Samsung 5123b modem is a bit shrouded in mystery. We know it's a Samsung 5123b because the modem name is in the baseband software version number. Samsung's page on the 5123 has very few technical details, and the details on there are misleading. For example, it says the modem has 8-carrier aggregation for the downlink and 4-carrier aggregation on the uplink. But no modem in existence right now has more than 2-carrier aggregation on sub-6 5G; that spec is really talking about LTE carriers.

For US readers, the most important question is whether it supports low-to-mid-band FDD/TDD 5G carrier aggregation, which all of the carriers will use next year to extend their 5G range and performance. Qualcomm's X60 modems have that.

Google's specs page explains there are two models of the Pixel 6 Pro, one with millimeter-wave 5G and one with only sub-6GHz 5G. (The millimeter-wave one is the one sold in the US.) The phone supports all the frequency bands that will be used by the three big US carriers over the next few years, but not how the channels can be combined.

Firmware dumps from the Pixel 6 Pro have now shown up on cacombos.com, and they aren't promising: there's no sign of the low-to-mid-band 5G carrier combinations, at least yet. They could still possibly be disabled in the firmware.

Whether it's the Samsung modem, Android 12, or both, the Pixel throws network-measurement apps for a loop. I used the app Net Monitor and the Ookla Speedtest consumer app, and in both cases the Pixel would frequently throw what appeared to be bad signal numbers, or no signal numbers, into the Android APIs.

Comparing T-Mobile signal strength was especially difficult as the Pixel wouldn't report LTE RSSI (a basic signal strength number) when connected to the 5G network. Still, though, I got enough samples to draw a conclusion.

Signal: S21 for the Win

Net Monitor takes signal samples every second, so I ended up with about 2,000 side-by-side samples of Verizon signal and about 350 side-by-side samples of T-Mobile signal. Signal strength was as strong as -53dBm and as weak as -125dBm.

Almost any way you cut it, the Galaxy S21 series did better than the Pixel at capturing 4G LTE signal. Here's the overall picture second by second; what it looks like if the signals were averaged out minute by minute; and who won if only bad-signal results (-100 or worse) were chosen. As you can see, in all situations the S21 side-by-side reported better signal strength, generally between 2-5dBm.

There's one exception. When the Pixel is on 5G, it doesn't report 4G signal strength properly. It does, however, often report a signal strength called NRRSRP, which in the non-standalone contexts we see 5G in today, generally corresponds to the 4G signal strength of the band used as the control channel. And there, I saw an odd result. Only when connected to 5G on the T-Mobile network, the Pixel 6 Pro showed better signal strength than the S21 Ultra.

So that had to be resolved with speed tests.

Speed: Still the S21

I also did 24 Ookla speed tests in different locations on Verizon's network, in a mix of 4G, 5G DSS and millimeter-wave locations, and seven on T-Mobile. The S21, once again, came out pretty clearly on top.

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The biggest differences appeared on Verizon mmWave, where the Pixel 6 Pro struggled to make it much over 1Gbps where the S21 approached or broke 2Gbps.

More importantly for my signal results above, on T-Mobile's mid-band "ultra capacity" network, the S21 did better on six out of the seven tests. It only failed the seventh one because the Pixel picked up 5G in one spot where the S21 was stuck on LTE. But that's why you do a bunch of tests—one outlier doesn't define the answer.

In the chart below, longer green bars mean the S21 won head-to-head contests more often. As you can see, almost all of our test categories had longer green bars.

What I Didn't See

Former Verizon and US Mobile PR manager Albert Aydin says that for him, any transition between LTE, 5G, and 5G UWB on the Verizon network results in a loss of all connectivity for 30-60 seconds. I did not see that; the Pixel dropped in and out of 4G and 5G second by second.

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PCMag's Steven Winkelman based his conclusions on the Pixel being able to maintain a connection in a wooded rural area where the S21 could not. I did my tests in New York City and used brick buildings to reduce signal strength. Most of the time, my phones were on mid-band frequencies. Rural areas generally rely more on low-band frequencies. So the Pixel may have better performance in low-band-only environments.

Conclusion: Qualcomm Beats Samsung

The numbers are the numbers, and the numbers say—for now—that the Google Pixel 6 Pro's modem-RF system aren't quite up to the standards of the latest Qualcomm products.

What that means for you is that in urban areas, the Pixel 6 Pro on the T-Mobile and Verizon networks won't have quite the level of performance of the iPhone 13 or Samsung Galaxy S21 line (much less the upcoming Galaxy S22). You'll see data connections struggle in weak signal spots of cities. The jury's still out in rural areas, given the two different sets of results we got.

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