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user_6d29f8
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Tuesday, April 11th, 2023 12:16 AM

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xFi doesn't seem to support advertised speeds over Wi-Fi?

​​Hello,​​

​​I ran a speed test from my xFi Advanced Gateway and see that we get 119% of the advertised 1000 Mbps that our plan gives us, which is great. However, over the 5.0 GHz Wi-Fi (standing next to the xFi) we only get 40% of the advertised speeds. See below:​​

​​Since the Wi-Fi seems to be a bottleneck for our speeds, I ran some LAN speed tests using 2 different apps I found on the Google Play Store (Cloudcheck and WiFi Speed Test), these seem to confirm that even if our xFi is reaching the 1000 Mbps advertised speeds for our plan, our devices would at most get 58% of that over the Wi-Fi. See below:​​


​​For weeks now my roommates and I have been experiencing slow speeds that seem to come and go throughout the day. We all work from home and use our Windows/Mac laptops over the Wi-Fi. There might be an issue with fluctuating speeds, but the Wi-Fi appears to be the initial bottleneck. Can the xFi model we have support 1000 Mbps over the Wi-Fi? If yes, could you please take a look at what is wrong with ours?​​

​​Thanks in advance for your help​​

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1 year ago

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flatlander3

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1 year ago

It's possible to get theoretically get 1Gbps over 5.0G WiFi, but there's a lot going on there.  You've got encryption overhead, and a lot of times you'll have both hardware and software limitations, especially on laptops.

It depends on which bus the radio is on.  If it's a PCIe card, it will be fast, depending on the architecture and how many things are on the same bus, but PCIe gen 1 can do around 2.5Gbps -- minus driver/os overhead.  If you are testing with a USB connected radio (common in laptops), you got a hardware limitation with bus speed there -- 2.0/3.0 USB difference too. USB ports are sometimes 3.0 ports, but are actually aggregated on a 2.0 hub, and how much traffic is on the USB bus matters as well.  Even if it is USB 3.0 on a 3.0 hub, with nothing else on it, the hardware is hard limited to 400mbps.  Even an 802.11 ax radio on a USB 3.0 port won't matter. You are stuck with the USB limitation.

The radio itself is important (some just work better than others), as well as what kind of signal you are getting, and the distance, plus the horse power of the CPU in what you are connecting to.  On a bench, back to back, with something like iperf, unencrypted, it is probably theoretically possible to get 1Gbps with 5.0 WiFi.  In the real world?  Expect something else.

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user_6d29f8

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1 year ago

Thanks for replying!

Let me play it back, to see I understood: "Achieving 1Gbps over 5.0G WiFi is theoretically possible, but in practice, there are many factors that can limit the speed, such as encryption overhead, hardware limitations, and signal quality. While it may be possible to achieve 1Gbps in a lab environment, in the real world, the actual speed will likely be lower."

So what would you recommend in our case? 

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flatlander3

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@user_6d29f8​ Take a look at your hardware you are using to test this.  If it's super important, and it's a laptop, you want to look at detailed motherboard specs.  What bus is the WiFi on?  USB?  Is there a half mini PCIe slot you can use for something like a RTL8188CE chipset card, and install that if you take your laptop apart?  If it's a desktop, they make regular PCIe x1 cards for bluetooth/WiFi too if you're got an open slot.

Honestly, I think you're confusing "speed" with bandwidth. Oh, marketing likes to talk about speed.....

Does 1.2Gbps service load a web page any quicker than 100Mbps service?  No.  It does not.  Nor does it actually do anything for you for streaming one stream on a single client.  At most, you'll pull around 50Mbps for an 8K video stream from a streaming service, so you could open 7-8 browsers, and start 8K streams in all of them, and max out 400Mbps -- with some caveats.  You might have to pull the streams from different locations because we're all throttling connections on web and streaming services, plus limiting the number of connections from a single IP address.  It also depends on gear in between you and who has the content.  There may be a bottleneck there as well.  

If you really want to see how close you can get to 1Gbps bandwidth on WiFi, you need different radio hardware.  While you're at it, change the gateway or use an access point that can speak 802.11ax.  You might get around 1.5Gbps at 5 feet, if you have that service capability, but there again, if you are using WiFi at 5 feet, why not just use an Ethernet cable??

1 year ago

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user_6d29f8

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1 year ago

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flatlander3

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@user_6d29f8​ Yeah, but, the radio in your device has to support it, and be able to transfer data at the bandwidth you want, so keep it in mind.  You're still stuck if you're USB 3.0. 

Quite honestly, there aren't a whole lot of use cases for 1.2Gbps on WiFi.  When "would" it matter?  Say you're downloading an Ubuntu DVD from a mirror, and at that particular time, there aren't a lot of users with active downloads on the mirror, and the mirror itself doesn't throttle a connection either with a firewall, or with their web server (most content providers don't run that way).  In that case, you might be able to max out bandwidth.

But if you actually look at your day to day activity, in real time, you'll find there's very few times when you actually max out bandwidth, if at all.  Gaming won't do it.  You just don't shuffle that much actual traffic gaming.  Web sites?  That's more delay from 3rd party content load and that latency, hops you got to get there, timeout from scripts you block, plus your own graphics rendering capability than actual data transfer.  

Worth it?  Meh.  Dunno.  Generally, for a multi-user service, you're concerned with the upload speed (others pulling data from you) which you just don't have on a consumer cable connection.  You can do that with fiber though.  Lease rack space too on a smoking fast backbone *(10G or larger bandwidth, super low latency) for not a whole lot of cash too.

(edited)

1 year ago

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XfinityNico

Official Employee

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553 Messages

Hello @user_6d29f8, thanks for reaching out for help on our forums! There are numerous factors that can affect speed over a Wi-Fi connection. Here are some great information to consider for improving network performance: 

 

https://www.xfinity.com/support/articles/improve-your-wireless-home-network

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1 year ago

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