Your router isn’t as fast as you think it is. Here’s why. – CNET

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 in some cases 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 smartphone, 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.

So, 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. (By the way, if you’re really want to dive in on networking, I’d recommend reading my in-depth look at networking basics.)

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 1,000Mbps, fast enough to transfer a Blu-ray disk worth of data (25GB) 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 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 an 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 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.
• 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, they must adhere to a lower speed standard in order to all 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 one 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

Advertised speed	Max ceiling speed	Max real-world speed (tested by CNET Labs using optimal settings)
1,000 Mbps	1,000 Mbps	1,000 Mbps
5,400 Mbps	2,167 Mbps	685.2 Mbps
3,100 Mbps	2,167Mbps	643.6 Mbps
2,533 Mbps	1733 Mbps	437.8 Mbps
2,400 Mbps	1,733 Mbps	504.4 Mbps
1,900 Mbps	1,300 Mbps	521.4 Mbps
3,200 Mbps	1,300 Mbps	601.7 Mbps
3,200 Mbps	1,300 Mbps	482.2 Mbps
2,350 Mbps	1,733 Mbps	381.7 Mbps
1,900 Mbps	1,300 Mbps	520 Mbps
900Mbps	450 Mbps	131.9 Mbps
1,000 Mbps	100 Mbps	100 Mbps

Advertised speed: The art of marketing

The question is why 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 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 or 260 km/h. And maybe the engine is capable at 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 the latest 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.

But the good news is that even those “slower” real-world speeds are often more 2 to 10 times faster (or more) than you need on many residential internet connections, which generally range from 20Mbps to 150Mbps (download) and 2Mbps to 20Mbps (upload). Netflix, for example, recommends 5Mbps for HD video streaming and 25Mbps for Ultra HD (4K) streaming. And this also means, getting even the most expensive router won’t necessarily improve your online experience, if you have a slow internet connection.

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

Dong Ngo/CNET

But adding up 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.” Tri-band routers are only necessary when you have a lot of 5Ghz clients (a dozen or more) being used at the same time. The D-Link DIR-890L/R for example, is a tri-band AC3200 router, suggesting a speed of 3,200Mbps. Completely untrue. The router has two 5GHz bands each caps at 1,300Mbps and one 2.4GHz band that tops at 600Mbps. Add those numbers together and you get 3200. 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 tri-band AC3200 router, though it supports fewer concurrent 5GHz clients before slowing down.

And, again, two caveats apply:

Cut all of those ceiling speeds in half anyway to account for real-world performance.
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.

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.

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 my internet comes into the house. This one-time time-consuming investment pays off big in the long run since allows all stationary devices (servers, network media streamer, game consoles, etc.) to connect via wired Gigabit connections, giving them the fastest network speed possible.

Use extra access points (or routers running in access point mode): 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 (given each room a super-fast wired connection,) adding access points is super 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 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 tri-band 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, etc.) 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.