iperf3 is a good to opensource software.
In order to install to your Synology. You have to check what kind of CPU your Synology is using. You can check from below link.
After you have checked your CPU model. You may download per-compiled iperf by jadahl.
From my case. My synology is
DS1815+. My CPU Model is
Avoton. My DSM Version is 6.1.
I went to http://www.jadahl.com/iperf/DSM_6.1/, and download below file.
Next, Login to your Synology. Go to Package Center. Click on the Manual Install.
Select *.spk (depend what model you are using). In my case, my file is iperf_avoton-6.1_3.2-1.spk. Click and install. Once installed successfully. It will appear in the Installed list.
Once your iperf3 installed and running successfully. You can access to your SSH and run as server/client depend your usage.
To Enable SSH, you need to go to Control Panel -> Terminal & SNMP -> Enable SSH service.
In Windows You can use putty program to SSH to your Synology and run your iperf3.
That’s all. Thanks for reading.