SyncToy is very slow between Windows 10 PCs

I have been using SyncToy for a very long time. It always worked fine. Also between two PCs, one with Windows 10 and one with Windows XP on a 1 GB network. But now, since I changed the Windows XP PC into a Windows 10 PC, SyncToy is extremely slow. That is to say, the Preview works well, but the transfer of files take about 10 secs per file: a write burst and 9+ secs doing nothing. Every time and on all folder pairs.
Other file transfers between the PCs are going very fast, just SyncToy not.
I have no idea what's going wrong here.

Does anyone know this problem and/or a solution? I appreciate your help.

Welcome to the forum. Try the built in robocopy it's a lot faster it can be av as it can scan on read and then write

Hi Samuria,

Thanks for the suggestion, but RoboCopy (GUI) is a complex tool for copying by specialists.
It does not have the specific synchronize functions SyncToy has (compare two folders, detect the newest files and files to be renamed).

It has simple /mir to mirror folder to folder

/MIR specifies that Robocopy should mirror the source directory and the destination directory. Note that this will delete files at the destination if they were deleted at the source.
This is no synchronisation! Sync works in two directions.

In addition: SyncToy works OK within one computer. But as soon as a folder must be synchronised with one that is located on another computer on the internal network, the sync is extremely slow. Between transfer of each item, there is a pause of about 12 secs. So, it is the network, not the tool itself!

Can anybody explain this or have an idea how to find the actual problem?