Is OverdriveNTool working good? There has been reports, that changing values with it doesn't really do much (same as Wattmann). But I guess it has been updated and working fine since then?
OverdriveNTool is working fine for me, but I basically only use it to adjust voltages. I use the registry mod for GPU and MEM clocks.
I can run the batch file as admin manually, and it works great.
When I run it in my startup folder it doesn't run as admin and doesn't work.
How are you getting it to run on startup as admin?
Use the task scheduler to execute your batch file at startup. See here:
https://superuser.com/a/929227