@nyonyo 

 

If you are only getting 300mbps connection from this router then likely you are connected to the 2.4ghz range.   The cause of this is quite possibly the WiFi card in your Laptop / PC

 

Check that the PC / Laptop can support 5ghz and if so force it to use this, 2.4ghz is very congested in most situations and will reduce performance.  5ghz connections should be 866mbps or 1300 mbps

 

Also worth noting that the WiFi speed is not an indication of the "quickness" of the connection, take this with a massive amount of suspicion...   Also what speed is your internet?   If you ISP is only giving you 50 / 80mbps then 150mbps WiFi is more than sufficient to cover that

 

 

@nyonyo 

"If you are only getting 300mbps connection from this router then likely you are connected to the 2.4ghz range"

 

Yes, I knew that all along, my adapter only supports up to 300Mbps, TL-WN821N, but again again and again, why I only get 144Mbps transmit and 300Mbps receive from Archer C80? My modem/router from ISP gives me, 300Mbps both transmit and receive

 

"Also worth noting that the WiFi speed is not an indication of the "quickness" of the connection, take this with a massive amount of suspicion...   Also what speed is your internet?   If you ISP is only giving you 50 / 80mbps then 150mbps WiFi is more than sufficient to cover that"

 

Again I never complain about the internet speed in my post, my contract is only 20Mbps, and I still get full +/-20Mbps around the house with this tiny weeny pity 144Mbps, my question is, why it only transmits 144Mbps?

BTW that tiny weeny 144Mbps CAN NOT deliver full 40Mbps (only 20 something) internet speed in my other house, another weird thing is, setting the transmit power to High and Middle give the same 144Mbps, while Low only transmit 7Mbps

@nyonyo 

 

I think you may be missing the point here..  link speed is completely fictional and doesn't give any reason to think that A is better / faster than B, let me try and explain more..

 

However in answer to your question, its likely channel width.    2.4ghz is limited to 11 channels and only 3x that wont interfere with each other (1 6 and 11).   This is based on 20mhz channel widths and will give you ~150mbps.  To get 300mbps you will need to increase the width of your channels to 40mhz, but this comes with added interference.  

 

There are quite a few good reasons to keep 2.4ghz on the 20mhz (150mbps) channel widths and this is selected by the Archer if you choose AUTO for the channel width.    Each vendor device will check the airspace and select what it feels is best for the situation, in this case the Archer is selecting 20mhz, the ISP 40mhz.   I have seen MANY occasion where 40mhz says its connected at 300mbps, but switching to 20mhz at 150mbps actually offers far better performance. 

 

If you choose 20mhz channel, its likely you can slip in amongst the other devices in the airspace (your neighbours), minimal overlap, minimal interference.  Say it selects channel 1, then only 2 and 3 can interfere with you.   If you force 40mhz channels, I can near guarantee it wont get 40mhz of space to use and interference will increase massively, you will need to choose channels 3-9 which means you get an interface from the ENTIRE 11 channels.   The end result a GOOD 150mbps is better than a poor 300mbps.

 

Ultimately it is your call, but you would need to test this to see what is best for you.

 

If you want the full 300 WiFi force 40mhz channels and that should sort it for you.

 

IMHO however, get a basic 5ghz card for $15 and use it instead, you paid for a decent router you may as well invest in a good WiFi card to use it.

Ok, I do plan to get 5GHz adapter, thanks a lot

BTW, what is the normal and acceptable link speed when I use 5GHz AC1300 adapter (Archer T4U)?

@Philbert 

I've got Archer T4U AC1300, but instead of solving the problem my big disappointment continues and multiplies...

while WN821N shows receive/transmit

300/270Mbps on ISP router

and 300/144 on Archer C80

My brand new Archer T4U shows even more surprising results,

receive/transmit for ISP router is 54/270Mbps

and for Archer C80 54/173Mbps (2.4GHz) and 54/867Mbps (5GHz)

This is very disappointing, what's the explanation for this?