RT-AC68U slower wireless speeds compared to wired

darkgiants

Occasional Visitor
I currently have three RT-AC68U's running the latest Merlin-WRT firmware that currently has slower wireless speeds compared to wired speeds. I am using AiMesh where one of the RT-AC68U is serving as my primary router, and the other two RT-AC68U's are serving as AiMesh nodes (wired). The internet speeds I am paying for are 650down and 20up. Through a wired connection, I am able to get ~710down and ~24up. However, on a wireless connection, I only get up to ~250-300down and ~24up. The devices that I am using for the wireless speed tests include the latest M1 MacBook Pro, iPhone 13, one of the latest ThinkPads (just to confirm it is not a device restriction of not supporting the latest WiFi standards). The devices these speed tests were run on do have the latest support for WiFi technologies. I also ran these tests by standing close (less than 5 feet away) from my primary RT-AC68U router. I also live in an area with very minimal WiFi congestion as it is deep in the suburbs.

I have already implemented the following wireless configurations:
  • 2.4GHz set on 20MHz channel bandwidth + custom control channel set to 11 (a channel with the least amount of traffic).
  • 5GHz set on a 40MHz channel bandwidth + customer control channel set to 149 (a channel with the least amount of traffic).
Any idea on what I can do to improve the wireless speeds? I feel like most of the typical settings are set unless I am missing something? Or is the slower wireless speeds compared to wired speeds a limitation of the RT-AC68U? Any input/advice is appreciated!
 
Last edited:

L&LD

Part of the Furniture
Your 5GHz settings are not set for maximum performance.

Use 80MHz width. Test with every Control Channel available.

Do not use any WiFi app. They (all) restrict performance when they're running, can't tell you which channel is the most heavily loaded (actual airtime used), and don't take into consideration non-WiFi interference.

Do test from at least 10' away from the router. They're designed to be used at a distance, after all.
 

ColinTaylor

Part of the Furniture
The internet speeds I am paying for are 650up and 20down.
I think you mean 650Mbps down and 20Mbps up.


  • 5GHz set on a 40MHz channel bandwidth + customer control channel set to 149 (a channel with the least amount of traffic).
Change the bandwidth to 80MHz. Use your M1 to connect to the 5GHz band on the primary router and then check that the link speed is 866Mbps.
 

darkgiants

Occasional Visitor
Your 5GHz settings are not set for maximum performance.

Use 80MHz width. Test with every Control Channel available.

Do not use any WiFi app. They (all) restrict performance when they're running, can't tell you which channel is the most heavily loaded (actual airtime used), and don't take into consideration non-WiFi interference.

Do test from at least 10' away from the router. They're designed to be used at a distance, after all.
I think you mean 650Mbps down and 20Mbps up.



Change the bandwidth to 80MHz. Use your M1 to connect to the 5GHz band on the primary router and then check that the link speed is 866Mbps.

I appreciate the responses! I have incorporated changing the channel bandwidth to 80MHz and making sure I am using the appropriate channel with the least amount of noise/congestion (which it seems I already was). After running another speed test, I was able to improve it now up to ~385down and 24up. However, is it still possible to improve that speed, is it still nearly a fraction of the speeds I can pull from a wired connection? For reference, I ran the speed test using the same devices referenced in my original post.
 

L&LD

Part of the Furniture
A full reset to factory defaults with a minimal and manual configuration as outlined below will give the maximum speeds possible for your router/network and client devices as a whole. But I do not think it will be appreciably better than what you're getting now. Your router's wireless technology is 8+ years old, after all. And wired is still king, even with current router hardware such as the RT-AX86U.

The following (older) routers are still more capable than yours, (IME); RT-AC3100, RT-AC86U. And the comparably priced RT-AX68U still beats all of them up (badly), for throughput and range.

[Wireless] ASUS router Hard Factory Reset | Official Support | ASUS Global

Fully Reset Router and Network

Fully Reset / Best Practice Setup / More
 

Tech9

Part of the Furniture
I was able to improve it now up to ~385down and 24up. However, is it still possible to improve that speed, is it still nearly a fraction of the speeds I can pull from a wired connection?

Don't waste your time resetting the router. Common 2-stream AC client can connect with up to 866Mbps link speed closer to the router and in real world Wi-Fi environment can do 420-480Mbps throughput. Sometimes more, depending on how lucky you are at the test moment. This is what your router can do to most clients. It works as expected. You can't get close to wired speeds with RT-AC68U, unless you use a rare 3-stream AC client. Keep 2.4GHz band @20MHz and 5GHz band @80MHz. Test the channels for both bands and lock the ones with most available throughput. Don't change your Wi-Fi channels often. The routers around you most likely run on Auto channel and will give you some space after some time.
 

jplw

Occasional Visitor
How are you testing? I have a 66U B1 Router and another as a wired node. My downoad speed is 400 Mbps via Xfinity. I just tested connecting at 5GHz 15 feet away from my node, using Xfinity's speedtest.xfinity.com and got 353.4. And my routers are older and slower than yours. However, if I let the router check speed to the same server (wired speed), I get 216.56.

One of these 2 tests is clearly wrong.
 

L&LD

Part of the Furniture
Note that the RT-AC66U_B1 router may be superior to the RT-AC68U (if it's the original model from 2013).
 

ColinTaylor

Part of the Furniture
One of these 2 tests is clearly wrong.
The built-in speed test is the incorrect one. It is a known limitation of the built-in speed test that it becomes CPU-limited at about 220Mbps on the RT-AC68U.

After running another speed test, I was able to improve it now up to ~385down and 24up. However, is it still possible to improve that speed...
Yes. As mentioned above, check that your client is connecting at 866Mbps. The RT-AC68U is capable of >500Mbps on 5GHz (I know because I have the same router and ISP speed as you).
 

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