Your router isn't as fast as you think it is. Here's why

CNET editor Dong Ngo explains Wi-Fi speeds and helps manage your networking expectations.

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Let's cut to the chase: Wired network connections will always be faster, more secure and more reliable than wireless.

If you want top speeds in your home, you'll want to save room in your remodeling budget for running gigabit Ethernet network cables (CAT5e -- or better yet, CAT6) to every room in your home. Ethernet is the only connection standard where the real-world speeds are very close to, or even match, the lofty theoretical speeds.

Of course, wired networking has several drawbacks. Wires are a pain to install, they're unsightly -- and it's just not fun to be tethered. And, of course, not every device is even compatible with wired Ethernet. For your tablet and phone, your streaming stick and even many newer printers, you will have to use Wi-Fi. But that's when you may find yourself poking along at slower speeds than you'd like. Also, even once you've upgraded to the best Wi-Fi solution (run network cables everywhere in your home) your online experience might not change much.

So what gives? Why the slowdown? You need to be aware of the huge gap among these three different attributes: real-world speed, ceiling speed and the advertised speed. There's also the broadband speed that you need to be aware of. (By the way, if you really want to dive in on networking, I'd recommend reading my in-depth look at networking.)

Editors' note: This article was originally posted on June 23, 2016, and is regularly updated.

Ceiling speed vs. real-world speed

The ceiling speed is the maximum theoretical speed of a connection standard determined in a controlled environment, without factors that would adversely affect the connection's throughput data rate. For example, the ceiling speed of a Gigabit Ethernet connection is 1,000 megabits per second, fast enough to transfer a Blu-ray disc worth of data (25 gigabytes) in less than 3.5 minutes. And in this case, the wiring that delivers this speed is protected inside your network cable by a layer of plastic, isolating it from the outside environment. This is why an Ethernet connection is able to deliver real-world speeds close to or on par with the ceiling speed of the standard.

Note, however, the network speed's rule of thumb: The ceiling speed of a connection is that of the slowest device in the chain. In other words, a connection is only as fast as its weakest link. So if you connect a Fast Ethernet device (100Mbps), like a Roku 3, to a Gigabit Ethernet (1,000Mbps) router using a network cable, the connection speed between the two (and only those two) will be capped at 100Mbps.

Wi-Fi, however, is totally different since it uses radio waves to transfer data. Wi-Fi devices share the same airspace not only with each other, but other home appliances as well. That means the speed of a Wi-Fi connection is subject to the Wi-Fi environment it's operating in. That's why your wireless speeds can flatline when you (or a neighbor in a nearby apartment) fires up the microwave.

Here are the main factors that adversely affect Wi-Fi speed:

  • Distance: The farther out, the slower the connection gets.
  • Signal loss (only applied to home mesh Wi-Fi systems): When an extender unit has to use the same band to both receive and rebroadcast signal at the same time, it will lose 50 percent of the original speed.
  • Obstacles: Walls and large objects will block the signals and shorten the Wi-Fi range.
  • Interference: The more devices of the same radio frequencies being used in the same area, the slower they get.
  • Compatibility: When devices of different Wi-Fi speed tiers, standards and manufacturers are used together, oftentimes they must adhere to a lower speed standard in order for all to function together properly.

This is why the real-world speed of a Wi-Fi connection is always significantly lower than the ceiling speed of the Wi-Fi standard being used. In my experience, at best, the actual sustained speed of a Wi-Fi connection is between a third and a half of its ceiling speed.

Take the Asus RT-AC68U, for example. It's a dual-band router, which means that it can operate on the 2.4GHz and the 5GHz wireless band. (The latter band is far less prone to interference from household items.) The top ceiling speeds on those bands in this case are 600Mbps and 1,300Mbps, respectively. That means the real-world speeds are closer to 300Mbps and 550Mbps, at best.

Advertised vs. ceiling vs. real-world speeds of popular Wi-Fi routers

Device name Advertised speed (Mbps) Max ceiling speed (Mbps) Max real-world speed, tested by CNET Labs using optimal settings (Mbps)
Reference wired Gigabit Ethernet connection 1,000 1,000 1,000
Linskys EA9500* 5,400 2,167 685.2
Asus RT-AC88U 3,100 2,167 643.6
Linskys EA8500 2,533 1,733 437.8
Asus RT-AC87U 2,400 1,733 504.4
Asus RT-AC68U 1,900 1,300 521.4
D-Link DIR-890L/R* 3,200 1,300 601.7
Netgear R8000* 3,200 1,300 482.2
Netgear R7500 2,350 1,733 381.7
Linksys WRT1900 1,900 1,300 520
Asus RT-N66U 900 450 131.9
Reference wired Fast Ethernet connection 100 100 100
* Triband router

Advertised speed: The art of marketing

The question is, why do all networking vendors always use the unachievably high numbers for the Wi-Fi ceiling speeds? That's because, as inaccurate as it is when it comes to the real-world speed capabilities of Wi-Fi devices, the ceiling speed is the only thing that's constant and therefore can be used to differentiate one Wi-Fi standard from another. However, to cover their asses, all networking manufacturers precede the top Wi-Fi speed number with "up to." It's kind of like the speedometer on your car: It may top out at 160 mph. And maybe the engine is capable of driving at that speed. But you're not going to be going anywhere near that fast in real life.

Take, again, the Asus RT-AC68U. It's classified as an AC1900 product because it uses 802.11ac Wi-Fi standard. The 1900 is derived by adding the router's top speeds on both of its bands: 2.4GHz at 600Mbps and 5GHz at 1,300Mbps. But that implication of "1,900Mbps" is completely misleading, because a Wi-Fi connection takes place on one band at a time (the router itself can work on both bands simultaneously, but each client can only connect to one of the two bands at a time) so at most, the ceiling speed of this router would be 1,300Mbps.

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The notion that this AC5400 router has a Wi-Fi speed of 5.3Gbps (or 5,400Mbps) is completely false.

Dong Ngo/CNET

But adding together the numbers is a networking manufacturer's favorite way of naming its routers. For this reason, a router with three Wi-Fi bands (two 5GHz bands and a single 2.4GHz band) can have an outrageously high number after "AC." Triband routers are only necessary when you have a lot of 5GHz clients (a dozen or more) in use at the same time. The D-Link DIR-890L/R for example, is a triband AC3200 router, suggesting a speed of 3,200Mbps. Completely untrue. The router has two 5GHz bands, each capped at 1,300Mbps, and one 2.4GHz band that tops at 600Mbps. Add those numbers together and you get 3,200. In reality, however, at best, the fastest connection you can get from this router is the same as that of any AC1900 router, like the Asus above.

This kind of naming convention is also confusing because a dual-band AC2400 router (1,733Mbps on 5GHz band and 600Mbps on 2.4GHz band) or an AC2600 router (1,733Mbps on 5GHz and 800Mbps on 2.4GHz) are actually faster than a triband AC3200 router, though it supports fewer concurrent 5GHz clients before slowing down.

And, again, two caveats apply:

  1. Cut all of those ceiling speeds at least in half anyway to account for real-world performance.
  2. Your AC speeds will drop to the maximum Wi-Fi speed of the connected device -- so if you're using a phone or tablet with 802.11g or 11n limits, expect even slower speeds.

Your broadband connection

Now it's obvious that you will never get the Wi-Fi speed that you think you pay for. But but the good news is that even those "slower" real-world speeds, Wi-Fi is often more than two to 10 times faster than you need on many residential internet connections.

This is because fast residential broadband connections generally range from 20Mbps to 150Mbps for download and 2Mbps to 20Mbps for upload -- if you want to find out how fast yours actually is, check out this quick tip. And this means, no matter how slow your Wi-Fi is, as long as it's faster than 150Mbps, which almost all Wi-Fi connections are, it's already fast enough to deliver your full internet speed. And this means that getting even the most expensive router won't necessarily improve your online experience if you have a slow internet connection. The only time a top Wi-Fi route would help is when you have ultrafast internet, such as fiber optic, with a top speed of up to 1Gbps.

But don't worry -- most of the time you don't need superfast internet. Netflix, for example, recommends 5Mbps for HD video streaming and 25Mbps for Ultra HD 4K streaming. On top of that a fast router also helps with local activities, such as wireless backups or data sharing.

Best practices

Now that you know what to expect out of a Wi-Fi router, here are some tips on how to get the fastest home network. These are what I do for my own home. Again, these only apply to the local network and in most case won't help with your internet connection.

Run network cables when possible: I actually have CAT6 cables running to every room in my house, with all of them converging in a single room where the internet comes into the house. This one-time, time-consuming investment pays off big in the long run, since it allows all stationary devices (servers, network media streamer, game consoles and so on) to connect via wired Gigabit connections, giving them the fastest network speed possible.

Use extra access points (or routers running in access point mode): Using access points connected to the main router via Ethernet cables is the best way to extend your Wi-Fi network while maintaining the best Wi-Fi speed. You can name the access point's Wi-Fi network the same as that of the main router (with the same password and other settings), if you want devices to move from one network to another automatically. If you've run network cables, giving each room a superfast wired connection, adding access points is easy.

Get a router and access point of the just-right standard: Currently AC1900 is the sweet spot for Wi-Fi. AC1900 routers are affordable and support the speed of the fastest Wi-Fi clients on the market, which is 1,300Mbps. If you have many Wi-Fi clients being used at a time, a triband AC3200 router will do, since you can can have multiple devices connected to each of its bands without adversely affecting performance too much. While it doesn't hurt to get a router with a higher ceiling speed (AC5300, AC2600 and so on) that won't result in faster Wi-Fi speeds. Routers with a ceiling speed faster than 1,300Mbps might be appealing thanks to new features (such as extra network ports, security and so on), but their Wi-Fi speeds are only for future-proof purposes.

Get a Wi-Fi system that uses a third dedicated band for backhaul: In a Wi-Fi system -- a product that has more than one hardware unit working in tandem to extend your Wi-Fi coverage -- backhaul is the connection that links hardware units together. If the system uses a dedicated band for this, signal loss (see above) will be minimized or eliminated. Currently there are a few existing systems that support this, such as the Netgear Orbi or the Linksys Velop. There will be more coming up in 2017.