Frame rate

FPS (Frames Per Second) is how many frames are displayed per second by a video device. Frames are still pictures that when sequence together form a fluid animation that is the basis for all moving media.

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 decrease the FPS temporary down to a complete stop for some seconds.

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
 * Do not run other programs while Minecraft is open
 * Turn off Aero in Windows Vista/7
 * Disable compositing on GNU/Linux (Compiz, Kwin, Clutter, etc.)
 * Check video card drivers and make sure antialiasing is turned off in the global settings

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".

As of Beta 1.8, Render distance is now a part of the environment approaching bedrock. At layer 27, the far render distance drops to normal, and normal to short. The gloom progressively closes in at layer 13 and below. At layer 1, the gloom 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.

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

FPS