Comcast Xfinity or AT&T Fiber? Which offers best internet service?

Houston is fortunate when it comes to internet access. Not only are there competing providers in most parts of town, but super-fast speeds of 1Gbps and higher are also available. Still, all gig-speed services are not created equal.

I recently had Comcast’s and AT&T’s gigabit broadband connections running at the same time in my swankienda and explored those differences. As I wrote in late April, AT&T wired our 1990s-era condo community for fiber, and once the network went live, I signed up and then was able to compare it directly with Comcast’s Xfinity — the cable-based internet service I’d had since it was Time Warner Road Runner in 1999.

Ultimately, only one could survive. I’m happy with the choice I made. Here’s how the two compared.

Both Comcast’s Xfinity and AT&T’s Fiber services offer download speeds of different tiers. Over the years, thanks to various promotional prices and Comcast’s nearly annual habit of boosting download speeds, I’d worked my way up to its 1-Gbps service. Regular readers know I have owned my own cable modem and router, avoiding the monthly gateway rental fee.

Whether you can achieve those speeds is another matter, depending on the modem/router you’re using, their placement in your home and the various devices you own. For example, while Comcast may sell you a 1.2Gbps service tier and rent you their top-of-the-line XB8 modem/router combo, if your devices support only the WiFi 6 standard or older, you’re unlikely to hit the advertised speeds.

I’ve got an iPhone 15 Pro Max that uses the faster WiFi 6E protocol, a cable modem that supports multi-gigabit download speeds and Eero Pro 6E mesh routers. Standing right in front of the Eero router connected to the modem, I get gigabit-plus download speeds on my phone. Had I opted to rent the WiFi 6E-capable XB8, the same would have been true, as I wrote in a review two years ago.

AT&T doesn’t charge you to use their BGW320-505 fiber gateway — which is good, because you don’t have a choice. You must use that device to connect to their fiber-optic network. However, you can use your own WiFi equipment and disable the gateway’s built-in radio signals. That’s also good, because if you crave the fastest speeds, AT&T’s device only supports WiFi 6 and the fastest my iPhone could get was 650 to 800 Mbps, not the 940 Mbps indicated in the company’s marketing materials. (An AT&T spokesperson told me earlier this year that the company’s next-generation gateway will use even faster WiFi 7 instead.)

When I connected my Eero routers to the AT&T gateway, their WiFi 6E signal provided download speeds close to that of Comcast, but not quite as good.

While I’d been mostly happy with Comcast’s download speeds over the years, the opposite is true for uploads. Cable internet relies on a standard known as DOCSIS, and the predominant version is 3.1. It allows for multigigabit download speeds but uploads are a fraction of that.

In Houston, the company recently boosted upload speeds in many neighborhoods to around 100Mbps — but only if you have the right equipment. My Arris S33 cable modem doesn’t support those faster uploads, maxing out at around 24Mbps. Had I used a different modem, or paid monthly for the XB8, I’d be better off. But I didn’t, so I wasn’t.

One of fiber’s top selling point is that download and upload speeds are symmetrical, or roughly the same. At the gigabit service tier, advertised upload and download speeds are around 940Mbps. But what I found is that often upload speeds were more than download — sometimes significantly so. When I was getting download speeds in the 600s, my upload speeds were in the 800 to 900Mbps range. With the Eero routers, uploads are often more than 1Gbps.

But that’s for now. A Comcast spokesperson said the company will roll out the next generation of the cable internet standard, DOCIS 4.0, in the second half of 2024 locally. Among other benefits, it will enable the symmetrical download/upload speeds that fiber offers. If pricing is similar to markets where DOCSIS 4.0 is already in place, it will be competitive with fiber — and will lack data caps.

Comcast charges $15 a month for its gateway, but you could pay as much as $25 a month if you opt for xFi Complete. This gets you the XB8, a WiFi extender if needed, cybersecurity protection and exempts you from the provider’s 1.2gigabyte data cap. As I wrote, you can use your own equipment instead of Comcast’s. You can pay $30 a month to avoid the cap and $10 per 10GB if you blow past it. (There’s a one-time, one-month grace period if you go over.)

AT&T doesn’t charge a gateway fee, but as I said, their equipment uses an older version of WiFi. As I did, you can connect a faster router to it, but it does involve digging deep into settings to disable the gateway’s WiFi and point the gateway.

It’s hard to do a comparison on cost because the two providers take different approaches.

Comcast offers promotional deals. For example, for the past two years I’ve paid about $60 for my internet service, but when that promotional period ended my bill jumped to more than $90 a month.

In the past, I’ve been able to negotiate with Comcast to drop to a lower tier, or even jump to a faster tier with promotional pricing. Over the years, I’ve found the company enters periods where it’s less apt to wheel and deal; we’re apparently in one of those now, based on my experience and what I’ve heard from other customers. I couldn’t get them to budge, and dropping to a slower tier wouldn’t save me that much.

This coincided with the activation of the fiber service at our condo complex and AT&T’s pricing, which doesn’t rely on promotions. Except for pass-throughs on some government fees, the price you see is what you pay, and it’s not tied to a promotional period. That said, AT&T says there will be no price increase in the first year. After that, no promises are made.

Both Comcast and AT&T offer internet discounts if you add their cellular services. I wasn’t interested in switching to Xfinity Wireless, but my wife has an AT&T phone line for her business. That got us a $20 discount on fiber. I’m now paying $65 a month for gigabit, symmetrical internet.

Advantage AT&T, until there’s a price hike

And so, after 25 years, I’m no longer a cable internet customer. That could change once DOCSIS 4.0 arrives. But for now, make mine fiber.