Is this game for Windows 32 bit? I have 64 bit and it's very slow and always freezes. When I opened my task manager to close the frozen game, it showed in the game name that it was 32 bit...
Can we know about your PC's specification? Or is it a laptop?
Try to reduce the game's resolution first and see if the FPS improves.
It's a Windows 8.1 laptop. Reducing the resolution did make the game faster, but when I tried to save at the beginning of the game, I was able to open the menu but it froze immediately after.