Idk about other games, but for GunZ setting the pc power plan to High Performance made fg run so much smoother for me. Try this, uncap your fps, make a private town room then write that number down, put your power plan to High Performance - restart pc - run gunz and write the new uncapped fps down then post the results if it actually improved.
Other stuff you can try: disabling xbox gamebar & and from Task Manager>start up disabling all of the useless programs that run on start-up, skype, spotify programs u dont use etc
But ye, if you're interested in gaming then it would be time for an upgrade, you could probably slip a new cpu and gpu for like $200 and get an extreme performance boost.
