Samba speed problems

I hope somebody can help me.
I just got a new Archer C7 and hoped it will increase the throughput for samba via LAN.
I am testing using my Laptop on Win10 as the client and my desktop also on Win10 as the server.
I mounted the desktop's drive as network drive on my laptop and run multiple tests with crystaldiskmark (using different sizes 4GiB, 16GiB). The sequential read/write is in the range of 70-80MiB/s, which is not the best in the world, but it would be ok for me.
The problem is that I don't get even close to this rates when copying using Total Commander, Explorer or TeraCopy. It's only ~20 MiB/s for read and ~35 MiB/s for write.
I tried many tweaks recommended for the NICs and samba settings without any noticable impact.

Why is crystaldiskmark transfering the date at much higher speed than what I get from other software?

The kind of traffic you are testing should not pass through the CPU of the router. So your only roadblock would be the switching capabilities of the router, which is not much configurable as far as I am aware.
Things you can check:

  • You can monitor the router resources during the copy with top or htop. High CPU utilization would raise concerns.
  • You can test with iperf to verify the real throughput without the hard disk speed factor.
  • You can use an individual switch to connect the PCs and test to rule out any speed restrictions from the switch of the router.

What is the CPU usage like during both tests: top -d 1 ?

Why do you think the router is to blame?

a little fly in the ointment, why not setup an nfs server on the win10 box and solve all your problems