Minecraft is a graphics-heavy game, so it can put a lot of pressure on the computer to render the display properly. When this happens the game takes longer to react to the player's movements and input, and everything suddenly gets slow and stuttery. This is called lag, and is probably something your kids have complained about to you at some point.
Luckily the game also gives you the ability to play around with the video settings, and these are the key to getting rid of lag. The trick is to get a nice balance between how good the game looks and how fast it runs.
The video settings can be found in the Options menu:
From version 1.7.2 onwards, the video settings menu looks something like this:
So let's go through the settings to see what they do, and how to set them to minimize the chance of lag.
This sets how detailed you want the images in the game to look. There are two options - Fast and Fancy. Fast makes the game run faster at the expense of the way it looks, while Fancy gives you a better looking game at the expense of how fast it runs.
The Fancy setting probably isn't worth the performance cost. To give you an idea, the image on the left is set to Fast and the one on the right is Fancy:
The world that you create inside Minecraft is really huge so loading it all into the game at once would make your computer work overtime. To get around that, only the bits that you need to see are loaded (rendered) at any one time.
The render distance is how far you can see, measured in chunks (a chunk is 16 blocks long x 16 blocks wide x 256 blocks deep) - the lower the setting, the better the game runs but you'll get a more foggy view of the world. Most computers work best at a setting under 12 (chunks) - start there and if you're getting significant lag, keep lowering the render distance until it improves.
Here's what the same view looks like as you increase the render distance:
This does just what it sounds like, it refines the lighting of each block so it blends together better and looks more natural. Set it to Minimum if you're experiencing a lot of lag.
Movies are made up of thousands of individual images that are displayed one after the other in rapid succession to make it look like they're moving, and that's how many video games work too. The framerate sets how many of these images (frames) are shown per second - the higher the rate, the more fluid the onscreen action will appear.
Minecraft can't operate at a framerate that is faster than what your monitor can display, and most work at around 60 Hertz (frames per second). So setting the Max Framerate at a lot higher than this is a waste because it will be working hard to render frames that you can't see anyway.
You can leave this off, it's a setting the allows you to use 3D glasses with the game.
This setting determines whether the player moves up and down (bobs) as they walk. Some people find that playing Minecraft makes them dizzy or seasick, and turning the bobbing off can help with that, but it won't have any effect on performance.
This determines the size of interfaces such as menus and the Heads Up Display (the hunger bar and inventory), and doesn't affect performance.
Changes the light level of the display, and has no effect on performance.
This setting determines whether clouds are displayed in your world. It can affect performance, so if you're experiencing lag then turn the clouds off.
Particles are things like rain, explosions, torch smoke, water drips and flames. Rendering them can take a lot of memory, so this setting specifies how many (and which) particles will be displayed:
- All - every type of particle will appear
- Decreased - only half the types of particles will appear
- Minimal - only the most important particles will be shown, such as blocks breaking and the hearts that indicate love mode for mob breeding
If you're experiencing lag then reduce the particles setting to decreased or minimal.
Pops the screen to full size, and doesn't have a huge impact on performance.
This setting syncs the framerate with your monitor's refresh rate, but it locks it in so you're better manually setting this yourself in the Max Framerate setting.
This smooths the textures of blocks, and a setting of 4 should be fine for most computers but can be reduced to help improve performance.
This adds visual detail to the game, but will only be effective if you have a certain type of graphics card (NVIDIA) so leave it off unless you know for sure that you do.
Summary of optimal video settings for reducing lag
So here's a good place to start when you're trying to optimize the performance of the game:
If you're still experience lag, reduce the render distance and framerate. Once you eliminate the lag, you can start to turn things like clouds, particles and smooth lighting back on or increase render distance one at a time until you get the right balance between the way the game looks and how fast it's running.
Other things that can help improve performance
If you're still experiencing significant lag in the game, try these:
Play in a small screen window rather than full screen
Hide the HUD (Heads Up Display - hunger bar, inventory, player's hand)
Play in an easier mode (less mobs, less lag)
Close all other running programs
Turn drops off for explosions (/gamerule doTileDrops false)
Cool down your laptop (make sure it gets plenty of airflow)
Install the Optifine mod (to optimize and stabilize video settings)
Play on a less crowded server