First of all, you have to check your FPS. To do so, hold "alt" and press "F" while in game. Now at the bottom left side of the screen you will see a number and either CPU or GPU (example: 27 [CPU]). The most important feature of this feature is that it will show you what part of your hardware is restricting your frame rate. If it shows [GPU] then it means that your GPU and graphics is restricting your frames per second. At this point you can try lowering your graphical settings (texture, animations, etc.) to increase your frames but this is somewhat not recomended as Planetside is quiet CPU intensive so leaving breathing room for your CPU is advised.

Now to understanding how Planetside interacts with your CPU. Planetside is poorly optimized for multi threading this means that if for example you have an i7 you will most likely see that only 20% to 30% of your CPU is in use and you are CPU bound in game. Now that you know this, there is another small quirk with the game:

If you lower your settings too much, (especially your textures) your CPU will have to work to downgrade them and then send it to GPU for rendering. This means that if you are getting really low CPU bound FPS in the lowest settings, while you have a really good GPU, you should test the game with high or even ultra settings to see if that will help.

Furthur notes on the CPU: Loewring shadow and flora will greatly help with FPS.

The optimum way to play planetside is too be GPU bound in warpgate and in low populated battles thus leaving breathing room for your CPU in larger battles.

To find the game file that you want to alter for graphical settings open the game launcher and find the wrench icon on the bottom left, above the loading bar. Click that and then click the "Open Game Firectory" button. This will show you the game files. now search for "UserOptions.ini" and open the file in notepad. In this file you will find all the player settings that can be changed.

NOTE: Official word from SOE is that this changing options here that are not available in the game menu may or may not cause instability (more crashes or drastic FPS drop) in the game. SOE is not responsible for instability caused by these changes.

This file is really a bare bones version of the in game settings and option menu with more options. In here you can turn settings off (like shadow or flora) and turn settings to ultra that are not availble in the game menues. This menu is really only for after you have figured out what will increase or decrease your frames and to make more extreme changes.

As I myself have not done much experimentatil with these programs I will leave it to this well structured video by Wrel to explain them. If you are worried about being banned for using these, it is important to know that these programs will not alter the game files but they will alter your hardware's performance based on the game's usage so being banned based on these is highly unlikely. Eventhough SOE has not released any official word on using these programs, I would say it is relatively safe to use them since they are being recomended (and used) by some of the most prominent community members.