1. Check for any malware:
https://www.malwarebytes.com/
2. Download Geforce experience and download drivers from there. You may have installed a wrong driver:
https://www.geforce.co.uk/geforce-experience/download
Use DDU to install a fresh installation of drivers.
how to use it: windowsreport.com/display-driver-uninstaller-windows-10/
download:
http://www.guru3d.com/files-details/display-driver-uninstaller-download.html
3. One reason why your performance maybe low is because of your parked cores. Simply, a parked core basically means it's disabled and you do not want that. Here is how to identify if your cores are parked/disabled:
Open up windows task manager > Click on the 'performance tab' at the top > at the bottom click on 'open resource monitor' > click on the 'CPU' tab at the top > On the right you may find 14 graphs. 12 graphs being your threads/cores. Make sure at the top of each graph where it says at "CPU 0", CPU 1 etc.. and make sure it does NOT say "CPU 0 - Parked".
If any of the 12 cores state they are parked or greyed out, do this:
Go to control panel > click on 'hardware and sound' > then 'power options' > then select 'high performance'.
If you can't find it then click on the 'hide additional plans' tab and it should be there.
4. Download Speccy and see if your computer recognises your GPU:
http://filehippo.com/download_speccy/
5. Make sure that you are not running on integrated graphics. Ensure your monitor is plugged into your graphics card and NOT anything else.