What is MU-MIMO and why would I need it?

Why shop for a specific router?
Why shop for a specific router? (Image credit: Windows Central)

What is MU-MIMO and why would I need it?

Best Wi-Fi Router (Image credit: Netgear)

The long and steady march of technology has brought newer and more complex acronyms to Wi-Fi routers. The latest is MU-MIMO, which stands for multi-user, multiple-input, multiple-output. Released with the 802.11ac Wave 2 wireless standard back in 2013, it is being employed in many new wireless routers and new devices, and it jumps the hurdles of older technologies to enable faster and more stable wireless connections.

What is SU-MIMO and MU-MIMO?

The majority of routers today employ SU-MIMO technology that, while providing wireless internet to multiple devices, has its limitations. SU-MIMO was introduced with the 802.11n wireless standard in 2009.

SU-MIMO allows you to connect multiple devices to the same wireless router, but the transmission of data can only happen to one device at a time. The router rapidly switches communications between devices — so fast that you normally won't notice — but when you're doing something that requires lag-free internet, you're going to see performance issues. For example, if you're gaming online while someone else is streaming video, you might end up dead before you have a chance to shoot back.

MU-MIMO amps things up by allowing your router to communicate simultaneously with multiple devices — no switching here. It's like each device gets its own virtual router. There are variations on MU-MIMO: 2x2 can handle two simultaneous streams, 3x3 can do three, and 4x4 MU-MIMO can handle simultaneous transmission with up to three devices. With MU-MIMO you'll find your connection is more stable and has a lower latency.

The downside of MU-MIMO

There are some things to consider before rushing out and buying a MU-MIMO router.

Many devices compatible with MU-MIMO will use two or even three data streams at once to connect to the router. For example, if you have a 3x3 MU-MIMO router, you can have a dual-stream device and a single-stream device connected at once. Connect any more MU-MIMO-compatible devices and you're again sharing data streams and experiencing SU-MIMO symptoms, like slow-buffering video and stuttering online gameplay.

Keep in mind that not all devices are compatible with MU-MIMO. It uses the 802.11ac wireless standard to communicate, so if your device is limited to 802.11a/b/g/n, you won't be able to take advantage of the tech's newest capabilities. Your device will still connect to the router using an older wireless standard, but you won't get the simultaneous streaming, improved speeds, or shorter latency. Keep in mind that even if your router uses 802.11ac, support for MU-MIMO isn't a given — so check the specs.

If you use all your devices in the same room, you won't be able to take advantage of MU-MIMO, as the streams cannot be differentiated when they're in close proximity to each other. Also, MU-MIMO is all about download speeds. If you're looking for something that increases your upload speed, this isn't it.

Do I need MU-MIMO?

Whether or not you need a router with MU-MIMO really depends on your internet habits and whether or not you have enough MU-MIMO-compatible devices to go with it.

If you live alone and don't often simultaneously game online, watch Netflix, and stream music, then you should be alright with a SU-MIMO router. If your household is packed full of modern gadgets, then it might be worth it — especially because many new devices coming out will be compatible with MU-MIMO. Even if you'll have more connections to the router than MU-MIMO can handle, an advanced router usually will be able to better handle more concurrent devices.

Which devices are compatible with MU-MIMO?

The list of devices compatible with MU-MIMO continues to grow, but for now, as far as Windows phones go, the Lumia 950, Lumia 950 XL, and HP Elite x3 are all compatible. Each of these phones uses two streams.

Dell's Alienware laptop line is compatible with MU-MIMO, as well as their Latitude 5000 and 7000 series. Acer's Aspire V and Aspire R laptops are both compatible with MU-MIMO, as is their Predator gaming line. These laptops all use two streams.

If you're not sure if your device is compatible with MU-MIMO, check the developer's webpage for a full list of system specs.

Which routers use MU-MIMO?

Now that SU-MIMO and MU-MIMO are understood, you might be in the market for a new router. There is not an enormous selection of MU-MIMO routers, but if you'd like an idea of where to start, we have a great router buyer's guide to help get you connected.

Router buyer's guide

Cale Hunt
Senior Editor, Laptop Reviews

Cale Hunt is formerly a Senior Editor at Windows Central. He focuses mainly on laptop reviews, news, and accessory coverage. He's been reviewing laptops and accessories full-time since 2016, with hundreds of reviews published for Windows Central. He is an avid PC gamer and multi-platform user, and spends most of his time either tinkering with or writing about tech.

  • New Dell XPS 13 (Kaby Lake) that uses the Killer 1535 Wireless also supports MU-MIMO. It's also popular with gaming laptops (Killer Wireless).
  • I wonder if the current Surface devices have support for MU-MIMO routers?
  • This is the specs page for the Marvell AVASTAR NIC in my SP3: http://www.marvell.com/wireless/avastar/88W8897/
  • I have it in my Acer Aspire F15.. It is awesome!
  • Awesome. I could use one of these.
  • streams and gaming? why the heck cant you use ethernet for those devices? I mean TVs and consoles, they are permanently fixed in place anyway
  • Some laptops for gaming don't have an Ethernet. Updated XPS 13 does not have Ethernet, for example. You are also aware that not everyone has access to Ethernet for their internet, right?
  • alright https://www.amazon.com/TP-LINK-Powerline-Adapter-Starter-TL-PA4010KIT/dp... besides, if you really want the best, thats ethernet for you, a usb-ethernet adapter seems like a wiser option for a gaming laptop, wifi will always become a problem down the road unless you're the sole user, but yea I got plenty of friends that refuse to use ethernet with their gaming laptops, even though they never even leave a desk
  • Also if you are an idiot (like me), and build or move into a house that doesn't have Ethernet run throughout. In a big house not only can this be a little costly compared to just using a WiFi router, it can be a real pain to have to run through so many walls. You are correct though, Ethernet is the fastest and most secure. Hopefully some future standard comes and negates this conversation with speed AND security.
  • Because people want their cake and eat it to.
  • The cake is a lie.
  • Let them eat cake!
  • For a good chunk of folks, ethernet wires all over the place aren't an option. I live in an older house, so drilling through beams and plaster isn't easy. It's also not allowed in my lease, because I rent the place. So unless all my devices are in the same room as my router (hint: they're NOT), than it's got to be wireless all the way. Not everybody is able to run wires, and won't pay for a network or telecom company to come out and do that (it's pretty costly!). Even a technophobe can read the numbers on their cable company supplied wireless modem, and put them into their new fancy wireless smart tv, or pay the neighbor kid a few $$ to set it up. That said, I would run the wires myself (and have in the past). I would absolutely love to have a 24port gig switch in the basement, and wire runs to each room and device.
  • https://www.amazon.com/TP-LINK-Powerline-Adapter-Starter-TL-PA4010KIT/dp...
  • I just bought and installed that device after running my own wire to an area that didn't have an Ethernet jack. It isn't hard work if you have the right tools.
  • The Netgear Nighthawk X6 (pictured in the article) doesn't have MU-MIMO. It uses XStream, which MU-MIMO devices can take advantage of but also improves speeds for non-MU-MIMO devices beyond what MU-MIMO can do alone. http://www.smallnetbuilder.com/wireless/wireless-features/32451-mu-mimo-...
  • I have a refurbished $49.95 AC router that pumps out about 300-700 mbps consistently to all of my devices.  Some of these ultimate routers cost well over $300 for a very little improvement in real world use.
  • I just bought a 3200 class router for just under $200. I agree, if you're spending over $300, you're probably wasting money, but the $200-$250 range has some really nice options. Considering my last router purchase was almost 5 yrs ago now, thats not too crazy...
  • Do Xbox one has MU-MIMO?
  • All your MU-MIMO are belong to Xbox.
  • Lol, seriously? Thanks for not much, :P
  • Somehow you managed to leave out ASUS RT-AC88U The best dual band router money can buy! 
  • So basically if my internet speed from my ISP is only 40Mbps, you're telling me I shouldn't waste my money right?