Slow SMB transfer speed (with Win11, Win10 works just fine)

Hi, I stumbled upon a few threads but none of them seem to adress exactly my problem.

My Problem: I have slow transfer speeds (read: 50MB/s, write: 20MB/s) with all 3 of my Windows 11 computers ↔ TrueNAS (latest Version)
I have a two Win10 computers which have “great” speeds (read/write: >100MB/s between those and TrueNAS).
Both windows 11 machines have no problem getting good speeds to each other or to the Win10 machines and also WIn10 to Win10 works just fine.

Win 11  -  good   -  Win 10
      \               /
     bad         good
       \        /
       Truenas
       /      \
    bad        good
    /          \  
Win 11 - good -  Win 10

Based on my testing I would assume that there is no problem regarding the hardware (cable, switch, network cards, ports) since every machine is capable of reaching the network limit if communicating with the right partner.

Any help would be highly appreciated.

Sorry - way too little detail to be able to make even the wildest guess about why.

I did not find a guideline which details I should provide and I was hoping that it is maybe a known issue or commonly known Win 11 (or TrueNAS Scale) misconfiguration which could lead to that behaviour (even though I did not find anything by myself).

Also I do not know which details could be interesting, since the only difference I see is the different OS (Win10 vs. Win11).

However, if you could let me know which specific details are needed, I would be happy to provide them.

First step: check with iperf3:

On truenas:
iperf3 -s

On Windows:
iperf3 -c [truenas ip]

Results should be nearly the same on all machines.

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@awalkerix might be able to help as I assume this is an SMB-related issue.

I don’t see any difference between Windows 10 and 11 perf-wise, so no I don’t think it’s an SMB issue (or at least it’s very much an uphill climb to get there).

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Ok, I just did the iperf3 check and from my main machine (Windows 11) I think I got pretty good results connection wise to the TrueNAS server.

Connecting to host 192.168.178.50, port 5201
[  5] local 192.168.178.216 port 53245 connected to 192.168.178.50 port 5201
[ ID] Interval           Transfer     Bitrate
[  5]   0.00-1.00   sec   106 MBytes   886 Mbits/sec
[  5]   1.00-2.01   sec   114 MBytes   947 Mbits/sec
[  5]   2.01-3.01   sec   113 MBytes   944 Mbits/sec
[  5]   3.01-4.01   sec   113 MBytes   948 Mbits/sec
[  5]   4.01-5.00   sec   112 MBytes   946 Mbits/sec
[  5]   5.00-6.01   sec   114 MBytes   946 Mbits/sec
[  5]   6.01-7.01   sec   112 MBytes   947 Mbits/sec
[  5]   7.01-8.00   sec   112 MBytes   948 Mbits/sec
[  5]   8.00-9.01   sec   114 MBytes   947 Mbits/sec
[  5]   9.01-10.01  sec   114 MBytes   947 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bitrate
[  5]   0.00-10.01  sec  1.10 GBytes   941 Mbits/sec                  sender
[  5]   0.00-10.03  sec  1.10 GBytes   939 Mbits/sec                  receiver

Windows 10

[ ID] Interval           Transfer     Bitrate
[  5]   0.00-10.01  sec  1.09 GBytes   933 Mbits/sec                  sender
[  5]   0.00-10.05  sec  1.09 GBytes   929 Mbits/sec                  receiver

So, these are pretty much the same.

Well, pardon me, I just found out what the problem was. I just realized that there is also one more difference in my setup…
Since many, many years I am using Directory Opus instead of Windows Explorer and yeah, this seems to be the bottleneck. If I copy the files via Windows Explorer I do get 112MB/s.
Thanks for the help!

The second time a different file copy program has been the culprit, in this thread is has been teracopy.

That seems to be a well known problem with Directory Opus which dates back to 2018 and has been fixed in the latest version (however, updating to the latest version requires a paid upgrade, and since I have been satisfied with everything so far, I saw no reason to do so).

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