GPU Tweak doesn't work properly on Windows 10 right now. Sometime the program will be updated in the future.
People recommend using MSI Afterburner, however I've ran into problems with it causing my graphics card to double it's overclock which I imagine could've blown it.
Use at your own risk, be careful when making profiles and to not constantly swap between them.
As a safety precaution, do NOT check 'start windows with overclock'
http://gaming.msi.com/features/afterburner
❤