Question about transfer speeds

Jherb

Occasional Visitor
Hello,
My setup is an ac86u with a laptop connected to one lan port. I send files back and forth to this laptop from another laptop that is connected via wifi.

I have noticed that when I send a file from the laptop (wifi) to the hardwired laptop, it gets a transfer speed of about 8-12 MB/s. Now when I transfer the same file in the other direction (hardwired laptop to wifi laptop), I get much faster speeds (around 40 MB/s). I am using the WIFi laptop to initiate both transfers.

Does it make sense that transfer in one direction is slower than the other? Why would this be the case?

Both computers are identical spec'd machines running windows 10 with the same settings. I've disable antivirus on both machines but no difference. I don't run anything fancy on the router. Just merlin 386.3, and I don't have any of the AI stuff turned on. So its a pretty basic setup.

Any help would be appreciated. thanks.
 

L&LD

Part of the Furniture
Test with different Control Channels on the Wi-Fi band you're on.

Don't look at any 'app' recommendations.

You're trying to find the optimum settings for your network environment. Which includes surrounding Wi-Fi signals, and non-Wi-Fi interference that no 'app' can detect or deal with.

Test each Control Channel you have available, keep good notes, go back to the one that was the best overall.

Remember, there is no 'perfect'. But if you do find it in your network environment, great! :D
 

ColinTaylor

Part of the Furniture
The WiFi signal strength of the router is much stronger than that of the laptop. So it's quite possible that the speed from the router to the wireless laptop will be greater than in the other direction. Try moving the wireless laptop to within 5 feet on the router and see if the speeds change.
 

eibgrad

Part of the Furniture
You shouldn't be measuring network performance using files anyway. That's going to introduce IO between the network and the file system, thus potentially skewing the results. Esp. when the two tests are writing to opposite systems. You need to use something like iperf, which tests *only* the network itself.
 

Jherb

Occasional Visitor
@ColinTaylor, I moved closer to the router and there is still significant asymmetry transferring. I tried other channels, but it didn't make any difference. When I hard wire the two laptops, transfer speeds shoot up as expected.

@eibgrad, I'm not trying to measure network speed as an end goal. I regularly transfer files between machines for work, and I noticed that I often have to wait quite a while. When I paid more attention, I realized it was only in one direction. That's why I did the file transfer test with the same file, to try to verify that it was not file related or something else I wasn't picking up on.

Thanks both for your suggestions. Hopefully, something will get uncovered as I play around.
 

eibgrad

Part of the Furniture
@eibgrad, I'm not trying to measure network speed as an end goal. I regularly transfer files between machines for work, and I noticed that I often have to wait quite a while. When I paid more attention, I realized it was only in one direction. That's why I did the file transfer test with the same file, to try to verify that it was not file related or something else I wasn't picking up on.

Fair enough. But if it was me, I would first measure the network speed independently of file IO to make sure it wasn't the network itself. If you get roughly comparable results in both directions, then test w/ files and vastly different results, presumably its due to differences in file IO efficiency.

Problem is, right now, there's no way to know how much, if anything, the network plays a role in the differences.
 

Tech9

Part of the Furniture
Same AC86U, PC 10ft away connected at 866/866 - 50-60MB/sec in both directions to my NAS. Just tested it for you. No difference.
Firmware Asuswrt 386_44470, no TrendMicro involvement, clean firmware with basic setup.
 

thiggins

Mr. Easy
Staff member
@Jherb and @Tech9 What Wi-Fi adapter are you using?

When testing using file transfers, it's important to use the same file or set of files in order to compare results. A folder of small files will produce very different results than a single large file.

@Jherb If you initiate file transfers on the wired machine, do you get different results?
 

Tech9

Part of the Furniture
The Wi-Fi adapter is USB 3.0 TP-Link T3U and I tested with the same movie file about 8GB in size. One single file for maximum read/write HDD speed and minimum effect on Wi-Fi speed test.
 

Jherb

Occasional Visitor
I am using the laptop adapter that is installed in the dell laptop. I don't recall what it is right now, but its an intel wifi card.
I am using a large 4gb file to transfer. When I initiate from the wired machine, I get the same asymmetry.
Moving closer to the router doesn't change things, as I was already about 10 feet from it.
Not sure why I have asymmetry, but thanks for all the inputs.
 

thiggins

Mr. Easy
Staff member
I have seen differences in Tx/Rx link rates with some routers and adapters that could explain this behavior. But if you are drag-and-dropping the file from the wired client to the wireless client and still seeing the same behavior as drag and dropping from wireless to wired, then the above explanation doesn't apply.

If it's any consolation, I have transfer slowdowns when copying my Thunderbird email file from my desktop to a laptop connected via a USB 3.0 Ethernet adapter. The transfer starts fine, but then slows to a c r a w l. I find using Wi-Fi to do the copy actually works faster.
 

Morris

Very Senior Member
Do the laptops have hard drives or SSD? Plug both laptops in, what speeds do you get?
 

Jherb

Occasional Visitor
Yes both laptops are SSD. I tried plugging both laptops in, and speeds are still asymmetric and slow. 11MB/s and 30 MB/s.

I also tried Iperf, and from the wireless laptop to the wired laptop, i get 95Mbits/s.

I really don't know what is going on. I rebooted the router, and unplugged all other devices. Do I need to reset the router. I hate to do that, but I'm not sure what is going on.
 

John Davis

Regular Contributor
Yes both laptops are SSD. I tried plugging both laptops in, and speeds are still asymmetric and slow. 11MB/s and 30 MB/s.

if you're getting assymetry even with both laptops on wired connections then it's NOT the router (as traffic will all be going via the internal switch, and that's good for full gigabit rates).

Is there any marked difference in terms of cpu between the two laptops (i.e. one's an i7 and the other an i3 or even lower). Also when both were on wired was this via built in ethernet or were you using usb ethernet adaptors?
 

Tech9

Part of the Furniture
Do I need to reset the router.

It's your call. I don't test router performance with custom firmware. I may test custom firmware features only. Swapped the AC86U with AC1900P, firmware Asuswrt 386_43129, no TrendMicro. Got about 44-52MB/sec in both directions with the same TP-Link T3U Wi-Fi adapter, connected at same 866/866. AC1900P did slower transfers, older chipset perhaps. Still fast router though. I don't know if there is a difference in wireless drivers, but current Asuswrt is few months newer code than Asuswrt-Merlin versions.
 

Jherb

Occasional Visitor
if you're getting assymetry even with both laptops on wired connections then it's NOT the router (as traffic will all be going via the internal switch, and that's good for full gigabit rates).

Is there any marked difference in terms of cpu between the two laptops (i.e. one's an i7 and the other an i3 or even lower). Also when both were on wired was this via built in ethernet or were you using usb ethernet adaptors?

Thanks. Both are i5s and this was with built in ethernet ports on the laptops.

Could there be something slowing down the internal switch? Is there a setting that can be tweaked?
 

John Davis

Regular Contributor
Thanks. Both are i5s and this was with built in ethernet ports on the laptops.

Could there be something slowing down the internal switch? Is there a setting that can be tweaked?

nothing to config for the switch on the ac86u (and I've got one here so know the internal switch is good for 1gbps)

Have you tried different cables to the laptops - just in case you've got a bad cable causing packet drops/retries

I'd use iperf3 to verify/test the network speed between the two laptops to begin with, and only once you know your link speed is good start chasing your file transfer issues
 

Jherb

Occasional Visitor
I'll try that. What should I expect with iperf. I ran it once already and got 95 Mbits/s from the wireless laptop to the ethernet laptop.
 

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