Frame rate

Frame rate (also known as frame frequency) is the frequency rate at which a video device produces unique consecutive images called frames. Frames are still pictures that when sequence together form a fluid animation that is the basis for all moving media. Frame rate is most often expressed in frames per second (FPS).

Low FPS will result in a “choppy” gaming experience, as far as looking like a slideshow in extreme cases. Difficult calculations (like blowing up huge loads of TNT in Minecraft) can temporarily decrease the FPS to a complete stop for some seconds.

How to check your FPS

 * Press F3 to bring up the Debug screen. Frames per second are listed after the Minecraft version at the top left. (Note: The debug screen is known to cause more load to your system, resulting in a lower FPS than you would have without the screen.)
 * Bring up the Options screen, select Snooper Settings, and look for 'fps'.
 * Various mods have options to show the FPS without other Debug screen information.

Increasing your FPS

 * Turn down your render distance (default keys: + . You can also press  and change it under options.)
 * Set in game graphics from Fancy to Fast
 * Turn off smooth lighting
 * Do not run other programs while Minecraft is open
 * Turn off Aero in Windows Vista/7
 * Disable compositing (= desktop effects) on GNU/Linux (Compiz, Kwin, Clutter, etc.)
 * Check video card drivers and make sure antialiasing is turned off in the global settings.
 * Hold down TAB. This will show the online players. (This only applies for multiplayer.) If there are a lot, this may be your problem. Try playing on single player.
 * Looking at the sky has also been known to increase FPS.

Third party methods
These mods are not guaranteed to work, can contain malicious files or corrupt your Minecraft program. Be careful when downloading and installing them.
 * OptiFine, is a mod which can substantially speed up and stabilize Minecraft's framerate. It has now been combined with Optimine
 * There are also guides available on how to manually increase FPS by editing various files in your system.
 * Not exactly a mod, but using a ramdisk greatly improves the performance of minecraft by storing the save files in RAM, which is much faster than a hard drive. However, there is some risk involved, if the computer crashes, you will lose all progress since your last backup to the hard drive.

Render distance
The render distance controls how many chunks of the world are visible at once, and can be set from the Options menu. The fewer chunks that are included, the faster each frame can be rendered, resulting in a higher FPS. The available distance settings, from nearest to farthest, are “Tiny”, “Short”, “Normal”, and “Far”.

The most distant terrain is faded into the sky color as if by fog, to avoid a sharp edge to the visible world; so this option is also known as "fog".

Note: Diameter = 2r+1

As of Beta 1.8, Render distance is now a part of the environmental void fog seen as the player approaches bedrock and The Void. At layer 27, the far render distance drops to normal, and normal to short. Void fog progressively closes in at layer 13 and below. At layer 1, the void fog begins just outside of your reach, and torches are ineffective for vision though still effective for mob stopping power. Bringing sunlight (block-based light such as torches does not affect the gloom effect) to the low layers removes this gloom effect. However, this "render distance" is only fog - it will not load less chunks, resulting in little to no FPS increase.

As of 11w48a, the gloom is no longer present in Creative Mode.

Video
FPS