Counter is your current in-game frames per second. It just counts how many times Directx's Present has been sucessfully called during the same second.
Clock is your local time in hours and minutes.
Running time is a time counter that can be reset from the fps or info tab. You can use it to see how long have you been playing, or how much time has passed since the last reset.
FPS Graph allows you to overlay a reduced size version of the current fps graph.
Text color lets you change the base color rgb values of the text elements overlaid onto the screen.
Windowed mode relocation moves the game’s main window so it ends up looking as if you were playing in exclusive full screen mode, it also removes the standard window borders, to achieve this effect you must configure the game to run at the same resolution as your Window’s desktop.
High priority process tells the operating system to raise the priority of the game program and all its threads, a game running on a very loaded system with many programs running in the background will benefit from this, but the same system running only the game will not.
Hide Windows cursor is the double cursor fix needed for some games after using alt-tab to switch in and out of the game.
This will prevent the windows cursor from showing over the game window, this can be annoying as games usually draw their own cursors and you can end up seeing more than one responding to mouse input in different ways.
This problem tends to happen when games are run in windowed mode. Not all games need it, and some recognized games will have this option disabled by default as they actually use the Windows' cursor.
Limit FPS sets the maximun fps of the game. This will limit the game's fps by making the rendering thread wait a variable amount of time.
English, Español, Русский options change the interface language, it also selects the language of the help web pages if they are available.
Change Laa (2GiB, 4Gib) allows you to change the PE executable flag that enables full 32bits memory addressing in games that are not enabled to do so.
The fpsc will detect the current status of the game executable which is shown in the button's description.
Some 32bit games can benefit from this change, changing this flag without checking first can and will break your game at some point when a memory allocation function gives the game a big memory pointer that is not ready to handle.
You should also check if the game actually needs it, some games never use more than a predefined maximun memory limit.
Take a look at the RAM usage graph in the FPS tab to see its memory usage before making a decision.
This option needs to close the game to perform the change, so you will have to reopen it afterwards, you may also need to have administrative rights to make changes inside the folder where the game's exe resides, otherwise the operation will silently fail and nothing will be changed.
If this is the case, you tried and wasn't changed, start the game as an administrator.