RT-N66U Slow Wi-Fi file copy speed

[Baz8755]

I am slightly confused by the following

I recently tried to copy a 1GB file from my NAS to my laptop and got a speed of 10MB/s which took well over a minute.

The same 1GB file from the same NAS copies at 100MB/s when using a wired connection.

All this I perfectly understand as wired is generally a lot quicker than wireless, but what is now confusing me is that the same laptop at the same location will quite happily return test results to SpeedTest.Net of 50MB/s.

So I am suspecting something is wrong and that a file copy over Wi-Fi should be quicker than 10MB/s but I am not sure what to check.

My laptop is a Lenovo T440s i7 512GB SSD running windows 8.1.

Ideas anyone?

Cheers

Baz

 

[enr00ted]

A few things first:
- Do you know how to check the link speed of your wireless ? (go to the wireless indicator -> right click -> open network configuration -> and then click on the adapter or network name listed there).
- Also what configurations do you have for your wifi in your router ?
- Do you copy over 2.4Ghz or 5Ghz ?
- Is the file a single large file or multiple files ?
- Do you have neighbours using the same wifi channels or band ?

Let me know if you need help how to find this information. Cheers.

 

[L&LD]

Are you sure about that 50MB/s?

I'm thinking it is closer to 50Mbps which is about 6.25 MB/s.

 

[enr00ted]

You copy at 100 MB/s (800Mbps aprox.) because the ethernet ports on your router are Gigabit wich make me assume your NAS is a Gigabit one.

On wifi with this router you can max at 37MB/s (300Mbps) with a 2x2 configuration or 56MB/s (450Mbps) with a 3x3 configuration aprox. This is the theoretical speed. More likely your laptop has a 2x2 configuration. (2x2 = 2 antennas | 3x3 = 3 antennas).

Anyway Internet connections are measured in Mega bits per second Mbps (Mb/s). Windows converts them to Mega Bytes per second MB/s.

1 Byte (B) = 8 bits (b) | This is why you divide by 8 to calculate the real speed.

 

[Baz8755]

I knew I was getting things mixed up, however speed is still very slow so I will do some digging when I get home tonight.

I know that it is currently set to 2.4ghz only and 20Mhz only, I may do some tinkering and see what happens

 

[L&LD]

You could try the test with your laptop plugged into the wall outlet and the power options on Performance vs. any other option.

But 10MB/s is decent enough.

What wifi card is in your notebook? What firmware version are you running on the router?

Have you ever reset the router to factory defaults and then manually and minimally configure the router to secure it and connect to your ISP?

Have you changed any settings on the laptop's wifi card?

 

[enr00ted]

I knew I was getting things mixed up, however speed is still very slow so I will do some digging when I get home tonight.

I know that it is currently set to 2.4ghz only and 20Mhz only, I may do some tinkering and see what happens

On 2.4 GHz and 20 MHz you get a max of 150 Mbps wich translates to around 18 MB/s. That is the theoretical maximum, so anything like interference, configuration etc can affect your speed, but you can't go past that limit.

If you have no neighbours or clear channels then you can try the 40Mhz which will double your throughput, in theory.

 

[Rankdropper84]

10 MB/s is probably about as fast as your going to get on the 2.4ghz band

 

[Baz8755]

OK, so I did some experimenting last night and found that if I change to 40mhz my throughput doubles to 300Mb/s.

However using 20/40mhz setting drops the speed back down.

So my question now is, what is the difference between the 20/40mhz and the 40mhz setting and what/if any negatives will leaving on the 40mhz setting have. Also will this affect any older hardware I may have?

It should also be noted that I am only running 2.4ghz and have 5ghz turned off, this was due to performance issues I had when I first bought the router so it has been turned off and left off ever since.

Cheers

Baz

 

[L&LD]

The 20/40 MHz channel width option is one which automatically chooses the best one for the wireless environment you happen to be in at that time (interference from other 2.4GHz networks). The best choice for the client, based on the default or selected options. And the aggressiveness of the router firmware you're running.

Selecting the 40MHz width option forces that mode. While it may seem to work with no problems for you, you are probably interfering with other nearby networks.

The throughput you state is not achievable actually. I think you are just describing the indicated connection speed. Test with an actual transfer between a wired computer or NAS and your wireless client to see the real throughput numbers.

 

[Baz8755]

The 20/40 MHz channel width option is one which automatically chooses the best one for the wireless environment you happen to be in at that time (interference from other 2.4GHz networks). The best choice for the client, based on the default or selected options. And the aggressiveness of the router firmware you're running.

Selecting the 40MHz width option forces that mode. While it may seem to work with no problems for you, you are probably interfering with other nearby networks.

The throughput you state is not achievable actually. I think you are just describing the indicated connection speed. Test with an actual transfer between a wired computer or NAS and your wireless client to see the real throughput numbers.

When I did a file copy it did appear to be twice as quick giving a speed on 24MB/s as opposed to 12MB/s.

However I have yet again hit stability issues and have moved back to flat 20Mhz.

As far as I am aware I am on a clear channel (according to Wi-Fi Analyzer).

 

[L&LD]

Your experience seems to indicate that the Auto width setting is properly selecting the correct channel width for your wireless environment, at least at this time.

WiFi analyzer or any other such tools are kinda useless because they don't show you all the radio frequency traffic, only the ones they think would interfere with wifi.

Simply try another channel and see if it gives you better results.

Btw, 24MB/s, while faster, is still only 192Mbps. Almost half the indicated connection rate as indicated previously.

 

[moonman]

Keep in mind guys that WiFi is half duplex. While the convention is to show the connection rate, actual maximum theoretical throughput is half that of the connection rate. So if you see 300Mbit/s, then your maximum theoretical throughput is 150 (minus network overhead, minus repeat overhead from interference and so on...)

 

[bbsc]

Keep in mind guys that WiFi is half duplex.

Not so simple.
Look:

Sorry for russian langpack, but the screenshot is quite understandable:
Router - RT-N66U, 5 GHz, 450 Mbit connection, minimum power, in the same room with laptop.
WLAN card - Intel Ultimate N 6300.
A 7 Gb mkv file is copied from LAN to WLAN.
Overall speed is 38-40 MB/s.

450 Mbps / 2 = 225 Mbps
38 MB/s * 8 bit/B = 304 Mbps

 

[Baz8755]

It would seem that I am doomed to slow and stable or fast and flakey with my setup.

I basically have 5 key devices that I am connecting
-Nexus 7 x 2
-Nexus 5 x 2
-Chromecat x 2
-LG TV
-Laptop with AN-7260

The only config that seems to be stable across all devices is 5ghz switched off and 2.4ghz fixed at 20MHZ on channel 13.
But this is of course a lot slower than I can achieve with 40Mhz, however I have tried several channels as well as auto but 40Mhz still seems flakey.
So last night I left 2.4ghz @ 20Mhz on a channel that works flawlessly and reenabled 5ghz @40mhz, everything seemed fine on my nexus 5 and it connected. However it disconnected and failed to reconnect later in the evening (I didn't even bother checking other devices).

There must be something I am missing as I was an early adopter of Wi-Fi (early 2000's) and have never had such issues before switching to a 2.4/5ghz system.

One thing (amongst others) is should I be using the same SSID & PW for both 2.4 & 5ghz. The experiment last night had the same although previously they have been different.

Cheers

Baz

 

[bbsc]

@Baz8755
It seems you don't really have any device for high-speed connection.
Mobile devices usually connect at 150 Mbps and Intel 7260 is known as unstable especially in 2,4 GHz band. Even if you're lucky and your 7260 works well - it's only a 300 Mbps card for 802.11n network.

Note that 2,4 and 5 GHz access points of your router work independently.
You'd better use different SSIDs for the networks.
Moreover, you'd better set each device to use only one AP - either 5 GHz or 2,4 GHz. In other case you may face the problem of frequent reconnection from one network to another.

 

[Baz8755]

Thanks,

I thought it was only the AC-7260 that had issues and not the AN-7260.

Luckily the only device I want the extra speed is the laptop with that adaptor so I will try re-enabling 5ghz@40mhz and just connect laptop.

I'll leave 2.4ghz@20mhz ch13 and let all the android devices connect to that.

Baz

 

[bbsc]

@Baz8755
Sorry, I've missed "AN" in the name of the card.
Don't know anything about AN-7260, but I've had an AC-7260 and it was terrible.

I think you're on the right way:
1. Set up two different SSIDs for 5 and 2,4
2. Try to get maxim for the laptop at 5 GHz (btw, 24 MB/s is a very good result for this card and router).
3. Try to connect mobile devices to 5 GHz if they can. If not - just leave 2,4 for them.
4. It's better to leave "auto" for channel number of 2,4 GHz, I think.

Always use WPA2/PSK and turn WPS off for security reasons.
Don't use high power, it doesn't help to achieve high speeds.

 

[Baz8755]

So far, so good

I have left 2.4GHZ @ 20Mhz Ch13

I am running 5GHZ full auto @ 20/40Mhz

Chromecast and legacy devices are happily connecting to 2.4Ghz

Android devices & Laptop connecting on 5Ghz (surprisingly the android devices did experience a noticible throughput increase moving to 5ghz).

Hopefully things will remain stable and fast

 

[noric]

Router - RT-N66U, 5 GHz, 450 Mbit connection, minimum power, in the same room with laptop.
WLAN card - Intel Ultimate N 6300.

I have the exact same setup as you: RT-N66U and an Intel 6300 card. I have a very poor throughput of about 6MB/s, though. Tested very close to the router and with no network interference at all.
May I ask you which firmware are you on? Did you notice any differences between firmware versions? I'm on RMerlin 374.40. Never tried 270 or newer 376 firmwares, so I don't know if it could make a difference.
Thanks.