RT-AC68U 2.4 ghz max wifi speed capped at 144 mbps

[Xdpker]

Hello, I have a RT-AC68U with stock firmware and I am having problems with my link speed. On all my devices, the maximum link speed on 2.4 ghz is 144 mbps. I have a variety of devices connected, androids, iphones, macbook airs, pros, chromecast and all of them show a maximum link of 144 mbps. I read that disabling b/g protection might help, but every time I try to uncheck the box and apply the settings, it doesn't take effect. Changing the channel bandwidth to 20 or 20/40 makes no difference, same link speed. The signal seems to be stable at 40 mhz. No dropping of signal or anything. Here is my 2.4 ghz settings page, let me know if any additional information is needed to diagnose my problem. Thanks!

My 5 ghz network is a different name and it's link speed is 585 mbps with my early 2014 macbook air.

 

[Xdpker]

On my Macbook air it says the channel width is only 20 mhz, but the wifi analyzer on my droid says it's 40 mhz. Link speed is 72 mbps on a new snapdragon 821 device.

 

[Xdpker]

Okay, so I was doing more research and apparently the router will lower the link speed if it detects other networks on the same channel? A good neighbor mode or something? I don't live near anybody else so I'm guessing it's my printers and soundbars causing the router to drop the link speed to 144 Mbps. Is there anyway to force my router into Greenfield mode in settings or using custom firmware? 145 Mbps is more than enough for me as my internet connection is only 100 Mbps and I can speedtest up to that. However my chromecast is connecting at 72 mbps causing lag and stutter when I am streaming HD content to my TV. Thank you!

*edit* on second thought I don't think this applies to me as there is an option to force 40 mhz channels width on the wireless settings, so I don't know why I'm getting link speeds max of 144 mbps. Getting even more confused now.

 

[RMerlin]

Please define in more details what your clients are. A quick look at your generic list shows a lot of devices which are only capable of a max of 144 Mbps on the 2.4 GHz band, so that would be perfectly normal.

If you want higher speed, you need to move to the 5 GHz band.

 

[Xdpker]

Please define in more details what your clients are. A quick look at your generic list shows a lot of devices which are only capable of a max of 144 Mbps on the 2.4 GHz band, so that would be perfectly normal.

If you want higher speed, you need to move to the 5 GHz band.

Oh I think you're right. Apparently Apple locks their devices to use only 20Mhz in the 2.4 Ghz band? That sucks, I just find it shocking that none of my devices can utilize the full speed available at 2.4 Ghz. I have the original Chromecast and a Oneplus 3T. Can you confirm that those have a maximum link speed of 72 at the 2.4 Ghz band? I couldn't really find any info on those beyond the basic specs. Thanks!

 

[RMerlin]

Oh I think you're right. Apparently Apple locks their devices to use only 20Mhz in the 2.4 Ghz band? That sucks, I just find it shocking that none of my devices can utilize the full speed available at 2.4 Ghz. I have the original Chromecast and a Oneplus 3T. Can you confirm that those have a maximum link speed of 72 at the 2.4 Ghz band? I couldn't really find any info on those beyond the basic specs. Thanks!

My original Chromecast connects only at 72 Mbps. It's a single stream radio.

 

[wouterv]

And I am not sure if the router will keep up 40 MHz bandwidth in crowded radio space.
Even set to 40 MHz it may scale down to 20 MHz.
Single stream / 20 MHz means 72 Mbps (some may report 75 Mbps), dual stream will then amazingly end up at 150 Mbps.

 

[KevTech]

I read that disabling b/g protection might help, but every time I try to uncheck the box and apply the settings, it doesn't take effect.

For b/g protection to stay unchecked you have to uncheck the box then set wireless mode to "N only" then apply setting.

 

[wouterv]

For b/g protection to stay unchecked you have to uncheck the box then set wireless mode to "N only" then apply setting.

Even in that way it seems to stay on, but you are no longer able to change the tick box:

 

[RMerlin]

Even in that way it seems to stay on, but you are no longer able to change the tick box:

View attachment 8070

That's because that setting doesn't do anything when your router is set to N Only (since that box is, as it says, only for b/g clients).

There's a bug in the logic Asus wrote as to how to handle that checkbox. Short answer is, it's automatically handled internally as needed. The webui checkbox is just non-intuitive in its behaviour.

 

[KevTech]

Even in that way it seems to stay on, but you are no longer able to change the tick box

You did not follow what I wrote in my post.

Uncheck the box then place mode to N only then apply.

 

[wouterv]

You did not follow what I wrote in my post.

Uncheck the box then place mode to N only then apply.

Excuse me, you don't believe me?

 

[KevTech]

Excuse me, you don't believe me?

Does not really matter as Merlin stated when set to N only the b/g is disabled hence why it is greyed out.

However, what I stated does work for me.

 

[wocram]

However my chromecast is connecting at 72 mbps causing lag and stutter when I am streaming HD content to my TV..

72 mbps should be plenty speed to play stutter-less 1080p (full HD) video's through your Chromecast!
I tested with bandwidth limiter and my Chromecast (1) plays HD quality video's faultless from around 2.5-3mbps (and up).