slow network transfer rates copying or moving small files QNAP Synology

Do you have a QNAP NAS?

can you copy or move very large files with gigabit speeds like around 100+MBps? (megabytes per second).
but when you copy small files the transfer rate drops to 10, 5, 1, or even 0kbps (kilobits per second).
sometimes sitting at zero for minutes?
If you use the app CX file explorer on your phone and the transfer rates are way higher than on your computer them the problem is on the computer.
have forums been telling you that this is normal? WELL IT'S NOT! they just don't know what to tell you.
I'd like to be able to give you an exact reason why this is happening, but it may have multiple causes.

Here's what I suggest:
check all cables and devices support the speed you are trying for.
check your MTU, is it the same on all devices?
drivers, updates, lan card settings, yadda, yadda, yadda!
check SMB versions on all devices.
disable encryption.
disable any compression.
check share permissions.
disable server signing.
if joined to a domain is the device still joined (this was an issue for me).
disable anti-virus scanning the NAS drives by letter and UNC (also an Issue).
If .jpg transfers are slow are thumbs.db accessible and changeable?

I read somewhere that creating a new profile can fix some NAS issues. in my case I logged in to my computer as a user that had never logged in before and mapped a drive. then logged out and back in as me and suddenly the speed issue is gone.

I did all of the above to get my QNAP transfer rates to what they should be.
My synology was having issues but not as bad. disabling virus scanning fixed the issue for it.