WEBVTT 00:00:00.200 --> 00:00:04.680 Snake oil that only exists to take your money seems to be everywhere in the tech world 00:00:04.680 --> 00:00:10.840 from $1,000 HDMI cables to heat sinks for your hard drives, I mean, come on. 00:00:10.840 --> 00:00:16.600 And our Wi-Fi equipment is often no exception as manufacturers keep finding ways to make our routers 00:00:16.600 --> 00:00:20.920 and access points seem more powerful than they actually are. 00:00:20.920 --> 00:00:24.480 With one of the biggest culprits being how they've implemented a technology 00:00:24.480 --> 00:00:28.100 called multi-user, multi-input, multi-output, 00:00:28.100 --> 00:00:32.100 or MU MIMO, Mu MIMO. 00:00:32.100 --> 00:00:36.940 So what exactly is it supposed to do and why does it suck? 00:00:36.940 --> 00:00:40.460 To answer, we had a conversation with our good friend Joel Crane 00:00:40.460 --> 00:00:43.660 and we'd like to thank him for his input. Thanks Joel, love you. 00:00:43.660 --> 00:00:47.740 Now to understand this, we're gonna have to go all the way back to the early days of Wi-Fi 00:00:47.740 --> 00:00:52.460 where our routers and gadgets each had just one antenna on them. 00:00:52.460 --> 00:00:56.140 They're basically just rocks. So let's say your router sent out a signal. 00:00:56.140 --> 00:01:01.180 To do this, the same signal blasted outwards in many directions and because of this, 00:01:01.180 --> 00:01:06.620 the different waves carrying this same signal would bounce around the room and arrive at your laptop 00:01:06.620 --> 00:01:10.000 or Nintendo DS or whatever at different times. 00:01:10.000 --> 00:01:15.100 Kind of like when you hear an echo in a large warehouse like this one. 00:01:15.100 --> 00:01:19.500 Now these signals arriving at different times caused undesirable interference. 00:01:19.500 --> 00:01:24.460 So a solution was introduced with the 802.11N standard in 2009 00:01:24.460 --> 00:01:27.860 called multi-input multi-output or MIMO. 00:01:27.860 --> 00:01:32.020 We've heard of that before. The simplest way to think about it is that both the client and the router 00:01:32.020 --> 00:01:35.860 would each have two antennas and two radios. 00:01:35.860 --> 00:01:39.580 This would allow the client to recombine these waves that arrived at different times 00:01:39.580 --> 00:01:43.820 into one much cleaner wave for better range and reliability. 00:01:43.820 --> 00:01:48.660 A solution called Maximal Radio Combining or MRC. 00:01:48.660 --> 00:01:53.220 Additionally, the multiple radios also meant that the router could also put different data 00:01:53.260 --> 00:01:56.460 on each stream to transmit information more quickly 00:01:56.460 --> 00:01:59.860 in a technique called Spatial Multiplexing. 00:01:59.860 --> 00:02:02.860 Sounds like a wrestling move. For a two radio access point, 00:02:02.860 --> 00:02:06.020 you could pick either MRC or Spatial Multiplexing 00:02:06.020 --> 00:02:09.380 depending on whether you needed to prioritize speed or range. 00:02:09.380 --> 00:02:14.420 However, if you had three antennas, you could actually use both at the same time 00:02:14.420 --> 00:02:18.820 using two antennas for MRC and a third for Spatial Multiplexing 00:02:18.820 --> 00:02:22.060 or all three for one technique or the other 00:02:22.100 --> 00:02:26.780 depending on your needs. It was so great. Now all this actually worked pretty well 00:02:26.780 --> 00:02:30.300 and resulted in significant speed and reliability improvements. 00:02:30.300 --> 00:02:35.500 However, the powers that be asked, hey, what if we use these different antennas 00:02:35.500 --> 00:02:39.300 to talk to different devices all at the same time? 00:02:40.900 --> 00:02:44.580 With that, multi-user or MU MIMO was born. 00:02:44.580 --> 00:02:48.340 But unlike standard MIMO, also called single user MIMO, 00:02:48.340 --> 00:02:52.140 MU MIMO simply does not work as advertised. 00:02:52.140 --> 00:02:57.620 Let me explain. The stated advantage of MU MIMO is that the messages being sent out from the router 00:02:57.620 --> 00:03:03.220 will arrive at all your devices at the same time, which is theoretically faster than waiting around 00:03:03.220 --> 00:03:07.700 for the router to talk to one device at a time, which is how traditional Wi-Fi works. 00:03:07.700 --> 00:03:10.940 However, for the messages to arrive at the same time, 00:03:10.940 --> 00:03:16.540 they need to be the same size. Something that very, very rarely happens 00:03:16.540 --> 00:03:20.140 since the different devices on your network are asking for different data, 00:03:20.140 --> 00:03:25.180 meaning that one device is going to be waiting to finish receiving a message after the others are complete, 00:03:25.180 --> 00:03:29.780 largely nullifying any advantage. Now on top of that, making the router deal 00:03:29.780 --> 00:03:34.900 with timing signals to all those different devices at once creates management overhead, 00:03:34.900 --> 00:03:38.340 adding latency and further cutting into any time savings. 00:03:38.340 --> 00:03:42.380 So the issue is while MU MIMO technology does work, 00:03:42.380 --> 00:03:46.900 technically, you're simply not going to see any real world advantage from it. 00:03:46.900 --> 00:03:52.180 In fact, many common clients don't even bother supporting MU MIMO, including many higher end ones. 00:03:52.180 --> 00:03:56.580 So the bottom line is this, don't prioritize MU MIMO support 00:03:56.580 --> 00:04:01.060 when buying your next router. You're better off looking for things that actually matter, 00:04:01.060 --> 00:04:05.300 build quality, customizable settings, and an aesthetic that makes your living room 00:04:05.300 --> 00:04:09.500 look like an evil layer so that you can impress your friends at your next house party. 00:04:10.620 --> 00:04:14.660 If you want them to be scared, I guess. All right, thanks for watching, guys. 00:04:14.660 --> 00:04:18.860 If you liked the video, disliked the video, do a neutral like. 00:04:18.860 --> 00:04:21.900 If the thumb, neutral thumb, is that a thing? 00:04:21.900 --> 00:04:27.820 Check out our other videos, comment below with video suggestions, and don't forget to subscribe to Tech Quicky 00:04:27.820 --> 00:04:29.820 and follow Tech Quicky.