Linksys AC1750 vs AC1900

Discussion in 'Networking & Security' started by Dosobye, Jan 11, 2020.

  1. Dosobye

    Dosobye Limp Gawd

    Messages:
    388
    Joined:
    Jul 29, 2010
    I'm looking at two routers.
    The EA6900 vs EA7400
    The EA6900 is the AC1900 and cheaper than the EA7400 which is a AC1750.

    Even their MSRP is cheaper on the AC1900 router.


    What gives? Isn't the AC1900 suppose to be better if so why is the 1750 more money.
    I'm trying to make a decision and kinda confused.

    Please advise
     
  2. bman212121

    bman212121 [H]ard|Gawd

    Messages:
    1,548
    Joined:
    Aug 18, 2011
    Not sure if you've already made your purchase or not, but here is some insight.

    Almost always the marketing numbers you want to look at are the series numbers. You have a 6xxx series device vs a 7xxx series device. It's very rarely that you'll see a discrepancy in that the higher the number the better / more expensive it is. So it would be like comparing a Ford focus to a Ford fusion. The focus might have a higher top speed, but the fusion is still a more expensive model. You'll have to look at other factors to see where the price difference comes into play. I'm not entirely sure the difference in features between them, but that would be up to you to see if any of that mattered.

    The other piece of the puzzle is the ACxxxx ratings. These are pure 100% marketing BS, and are generally worthless to look at. They basically tell you nothing, and are easy to manipulate to help lie about their product. Let's actually dig into the two routers ratings.


    EA6900
    "N600" 2.4ghz
    1300mbps 5ghz

    EA7400
    "N450" 2.4ghz
    1300mbps 5ghz


    So for answer #1, in theory the 6900 has slightly faster 2.4ghz performance. But does it really? The answer depends upon your clients.

    We'll pull up the wonderful wiki MCS charts to figure it out.

    https://en.wikipedia.org/wiki/IEEE_802.11n-2009

    Search that chart for 600mbps, and you'll see one option of being able to do that. It requires 4 spatial streams, a full 40mhz channel, and short guard interval. So that tells me two things, first things first, there is only 3 antennas on the device. That must mean that the 2.4ghz antennas are likely internal ones. There needs to be 4 antennas minimum to support 4 spatial streams, and there isn't that many externally. The other thing that tells me is that you will never get that kind of performance out of it, ever. Just about every device in existence has settling on having 2 antennas in it, with some really cheap devices only having one. The only devices with 3 antennas are high end expensive laptops (MacBook Pro) and certain desktop adapters can have up to 4. So in the most common scenario, your device will likely have 2 antennas capable of using 2 spatial streams. That means if you look at that chart, and look at the fastest speed for 2 spatial streams, you'll see it on MCS 15. That means for all intents and purposes, you will only ever see 300mbps max connection in 2.4ghz. But even that's basically a lie. The device can run 40mhz channels, but it's highly not recommended unless you are in the middle of nowhere with no other routers / APs nearby. If using 2.4ghz you should be using 20mhz channels, which means actual max data rate would be 144mbps.

    So using that same logic, but applying it against the EA7400. This device claims N450, which if we look at the chart would 3 spatial streams, with the same settings as the other AP. Once again your client is almost guaranteed to be 2 antennas, so it's a moot point the router can do 3. The more interesting part here is that the device does have 3 external antennas on it, so we really can't guess whether those are for 2.4ghz or 5ghz. One of those is probably internal, one external. Usually you'd want external 2.4ghz for range, and 5ghz internal for density. But in a residential environment that could potentially be swapped around.

    The 5ghz on both of these devices claim the same speed. However using AC this can get more complicated.

    If you look at the chart for 802.11ac, you'll see that there are 3 different combinations to come up with that speed.

    https://en.wikipedia.org/wiki/IEEE_802.11ac


    There is:

    MCS 7, 2 streams, 160mhz wide channels
    MCS 9, 3 streams, 80mhz channels
    MCS 7, 4 streams, 80mhz channels

    So right off the bat, we know for a fact that the EA6900 has 3 antennas on it for 5ghz. So we know that the last option isn't possible. But we also know that the first option is very unlikely (Probably 95%+ of AC devices cannot use 160mhz channels. This goes for both the router and the client side. Even if they could it's highly not recommended for the same reasons as using 40mhz in 2.4ghz) The other thing with #1 is that it's not actually the fastest speed you could get using 2 antennas, so if it were up to marketing you can bet they would be calling it 1733mbps because it would be capable of doing so. So that means that #2 is our answer.

    The EA7400 thankfully states right on the product page that is a 3 x 3 spatial stream AC device. So that means we know that it is also configured exactly the same as the EA6900. So regardless of the fact that once again, your client can only use 2 of the 3 streams, both devices would perform the same if you device could use all 3. So if we look at the chart for the fastest 2 stream, we know it's the row with MCS9 and 2 spatial streams. However, we already determined that neither one of these devices can do 160mhz wide channels, as their advertised speed is using 80mhz channels. So we need to look in the 80mhz column, not the 160mhz column, to find the top speed we'll get. That is 866.7mbps. So in most scenarios with a typical device, that's what you'd expect to get.


    So we've determined that the most typical scenario with each of these devices is that both of them will use:

    2.4ghz
    144mbps

    5ghz
    867mbps

    So a more "truthful" marketing rating would probably be 144 + 867 = 1,011. But that assumes you're using both your 2.4ghz and your 5ghz bands, if not then the number above show what you'd actually expect in a best case scenario.

    The point here is that speed wise, these devices are identical. Yes technically the EA6900 could be faster in an ideal scenario, but in reality it will make zero difference in the real world. And if you caught on by now, paying for a router that supports 3 x 3 spatial streams over a router that only supports 2 x 2 spatial streams, won't really make a difference in speeds because they are both limited by the client. There can be some slight advantages to having 3 antennas on a router because it can better tune the signal to get more strength, but it's a moot point because placement of the AP will make a much bigger difference in signal strength than an extra antenna ever could.

    Which to buy really depends upon what other features they have, or seeing if you can find where someone actually tested the device in the real world. Linksys isn't nearly as truthful as they used to be, and there are a large number of other factors that could play into coverage, but they no longer state any of that information in their user guides. I can't tell you if one will give a stronger signal than the other because there isn't any way to know without physically testing it.


    TL;DR The ACxxxx ratings are 100% marketing BS, and both of these devices and most other AC devices will end up performing very similar in the real world. If they are different it has nothing to do with the ACxxxx moniker.
     
    dawsonkm likes this.