In game fps
In game fps
Steam functions similarly to other tools, likely accessible beyond purchased game titles.
For BF4 the command is perfoverlay.drawfps 1. It displays live FPS based on average over time. For that you need Fraps. If you want the current value, add a text file called user.cfg in the Program Files folder with your game installed. Insert any console commands you need there, one per line. For BF3 the equivalent command is Render.DrawFps 1, same for all previous BF titles.
For an NVidia GPU, you can turn on a FPS counter in ShadowPlay.
fraps only really impacts your fps if you are recording....there is a settting believe shortcut F11 to do a benchmark. it records your max/min and avg fps and then save the info to a file