Qualcomm Atheros wireless network adapter speed.

Mia2080

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Sorry if this has been asked and answered but I could not find anything that fit my problem.

PROBLEM: I bought a new ASUS laptop model X551MA. The atheros wireless network card that came with it is rated at 300 Mbps. But in the wireless status it only shows 72.2 Mbps. As luck would have it, I had a spare atheros card and popped that in. It too shows 72.2 Mbps.

So I bought a new TP-Link USB wireless adapter. Its rated at 300 Mbps and it shows up in the wireless status as 292 Mbps. So this adapter seems to work fine.

QUESTION: So why am I losing Mbps on the Atheros but not the TP-Link? They are both rated at 300 Mbps but the atheros only shows up as 72.2 Mbps. Speed testing both confirms that I am losing Mbps. The Atheros has a download speed of about 1 Mbps and the TP-Link was around 17 Mbps.

Two Atheros cards, both rated at 300 Mbps, both show 72.2 Mbps.
One TP-Link card, rated at 300 Mbps, shows 292 Mbps.

THINGS I'VE TRIED: I'm running Windows 10. I restored to factory default of Windows 8. I've updated the drivers, deleted the drivers, reinstalled the drivers. Even swapped out the card with another Atheros card. Same issue. I also swapped the black and white wires on the card and it still shows up as 72.2.

Any thoughts?

Not sure if this is right but here is a photo of what I'm talking about:
 
Those number are what is called a MCS index....you can look up the tables.

These represent the negotiated rates between the pc and the router. I am unsure what 292 means but 72.2 means the pc is getting good signal but it has detected a signal on a adjacent channel so it has moved to 20mhz from 40mhz.

Still even if it could get 40mhz it will still only connect at 150m. The 300m requires 2 overlapping data streams. Since it did not negotiate this it means ether router or pc nic does not have 2 or more antenna or the signal is not good enough to get it to work.....I suspect your router does not support 300m.....or this is the dual band lie of 150m+150m

You could try to go into your router and force it to use 40mhz channels. You may get it to negotiate a faster speed but now you likely have interference from a neighbor so the real life thoughput may be slower.
 

Mia2080

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I don't have a router. I'm using a public wifi. Comcast xfinity to be exact. Its pay as you go. I can't access router info from them. I've included a pic to let you see what I'm looking at. The card on the left has the problem. Its rated at 300 Mbps as per the manufacturer's specs but only showing 72.2 Mbps. The card on the right is rated at 300 Mbps as per the manufacturer's specs and is showing 292 Mbps which is close enough.

I'm just trying to understand if this is normal. I tried two Atheros wireless adapters, both were rated at 300 Mbps, and both showed 72.2 Mbps. The TP-Link works as advertised.


 
If you have no access to the router then you can do nothing if the router has limitations set.

Again this is a negotiated rate, the router and the nic card will try to get the best combination both can run.

This is one of the many MCS charts, this one has 802.11ac on it also.

http://www.wlanpros.com/mcs-index-802-11n-802-11ac-chart-3/

So to get 300m you must run 40mhz channels, have 2 data streams and have a signal good enough to run QAM-64 encoding. This would be a MCS index of 15.

If you look the only place you find 72.2 is on the mcs index 7 line. It shows you are only getting 20mhz. It also means there is only 1 data stream.

The 292 number is in there on 802.11ac but unless the device is really 802.11ac then this is some form of abnormality.

In any case if you have no access to the router and it is negotiating these rates that is all you are going to get.
 

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