upload speed is 40% slower than download

[dieter]

I have an older Lenovo T520 with an Intel Advanced N-6205 controller. I get 240Mbps down and only 140Mbps up.
I have a hardwired computer which bets about 800Mpbs up and down on my fiber connection.
Both laptop and hardwired computer connect to the same Asus router.

I have checked all the Wifi controller setting, and everything seems normal. The driver is also the latest, but old. There are no background apps running while doing the speed test.

Is this normal for the N6205, and any other thoughts?

Dieter

 

[Datalink]

The N 6205 is only capable of 300 Mb/s according to Intel's specs:

Product Specifications

quick reference guide including specifications, features, pricing, compatibility, design documentation, ordering codes, spec codes and more.

ark.intel.com

 

[dieter]

I know that, but why am I getting 40% lower upload speeds than download.

 

[degrub]

Try running iperf between your two machines to eliminate issues. Use one as the server and other as client. You can run parallel streams to saturate the link. Do it wired through a switch first and then try the wireless through the router. Post what you find out.

 

[dieter]

I'm not familiar with iPerf. Here are my speedtest numbers:
1. Hardwired: 800 Down - 752 up
2. Wireless 2.4G: 110 down - 114 up
3. Wireless 5G Channel Bandwidth Channel BW 20/40/80 auto; Control Channel = 44:
208 down - 134 up
4. Wireless 5G Channel Bandwidth 40Mhz; control channel = 157Mhz:
235down/153up

The Wifi Analyzer shows channels 34 - 50 for 5G, at about -45 dbm at channel 44.
Channels 3 - 11 for 2.4G, and abut -35dbm down at channel 7.

Wifi Anazlyzer shows no other users on my 5G channels while these tests were performed.

I have tried several different driver configs, but all with the same result.

What additional info would iPerf give me?

Dieter

 

[degrub]

ipef lets you take the internet and the router (other than the switch which should run full line speed) out of the equation for bandwidth troubleshooting.

Have you tried the same speedtest using the LAN port instead of the wireless on the laptop ?

 

[dieter]

My LAN speeds are shown in my 1. above:
1. Hardwired: 800 Down - 752 up

 

[degrub]

Have you looked in the Lenovo and Intel forums for any similar issues with that wireless card ?
the AP seems to be providing plenty of signal to to laptop.
It could be a weak laptop transmit radio or just an issue with that model transmit radio. You might get a usb wireless adapter and see if that addresses it. What is the AP configured for ? Anything below wireless N ( G, A, B for example) ? If it is see if turning off the lower protocols helps.

 

[dieter]

Thanks, I'll keep hacking at it.

 

[Tucu]

Asymmetry is not unusual. With my notebook syncing at 867Mbps using an Intel AC 7265 (2x2 AC) I get ~530Mbps from router to notebook and ~330Mbps in the other direction. In my phone (1x1 AC) syncing at 433Mbps the split is around 330/200. All the tests done with iPerf running 8 threads.

 

[dieter]

What causes this asymmetry on my laptop?
I have a 5G Chromebook which does not have this problem. Running the same speed test on it, I get 189Mbps down, and 193Mbps up!

 

[dieter]

I installed iPerf3 and got 180Mbs in both directions. Not sure why Speedtest gives me a consistent download speed of 235Mbps.

 

[Tucu]

I installed iPerf3 and got 180Mbs in both directions. Not sure why Speedtest gives me a consistent download speed of 235Mbps.

Try using more parallel client connections in iPerf (like Speedtest does). Try passing "-P 6" to iPerf. The asyimmetry is stronger with more network connections.

 

[dieter]

Not sure how to interpret the results.

 

[dieter]

My interpretation of these parallel stream results is that with iperf over Wifi, it still sends at 192Mbps. This tells me that maybe the problem is with Speed Test?

 

[Tucu]

By default iPerf runs for 10s; it outputs the result of each connection and a sum of all connections every second. At the end it outputs a summary including the average speed. That is the 192Mbps at the end of your screenshot.

This test is in one direction; you have to compare with the results taken by passing a "-R" option to compare uploads and downloads.

 

[dieter]

With the -R option, not sure who is sending. There is a definite difference.
But what does it mean?

 

[dieter]

With the -R option, does the server not send (upload)?

 

[Tucu]

By default the client sends. With the -R option the server sends.
Is your laptop acting as the client and your wired PC as the server?

 

[dieter]

The laptop is the client.