If I were you, I would upgrade to Windows 10 as soon as possible, and if you're still having problems, then come back and ask for help. There have been a huge amount of performance and stability improvements since Windows 7 SP1. I know I had some noticeable performance improvements jumping from 8.1 10.
If you can't do that immediately, you may like to check that all of your drivers are up-to-date, and it wouldn't hurt running CCleaner either: https://www.piriform.com/ccleaner
Either visit the manufacturers website, or use something like Driver Booster to search for updates: http://www.iobit.com/en/driver-booster.php
Furthermore, do you have any MODs installed?
If you can't do that immediately, you may like to check that all of your drivers are up-to-date, and it wouldn't hurt running CCleaner either: https://www.piriform.com/ccleaner
Either visit the manufacturers website, or use something like Driver Booster to search for updates: http://www.iobit.com/en/driver-booster.php
Furthermore, do you have any MODs installed?