Simulation distance controls how far from your player the game actually processes world mechanics. Measured in chunks (each chunk is a 16×16 block area), it determines the radius around you where mobs think and move, crops grow, water flows, and new entities spawn. Anything beyond that radius is frozen in place, completely paused until you get close enough to wake it up.
Simulation Distance vs. Render Distance
These two settings are easy to confuse, but they do very different things. Render distance controls how far you can see. Simulation distance controls how far the world is actually alive. You can set your render distance to 20 chunks and see terrain stretching to the horizon, but if your simulation distance is only 8 chunks, everything beyond that 8-chunk radius is a static image. Mobs stand motionless, farms don’t grow, and machines don’t run.
This separation exists because rendering terrain (sending visual data to your GPU) is far less demanding than simulating an active world. Every active chunk needs its entities tracked, its random block updates processed, and its spawning rules checked, all of which hammers the CPU. Letting you see far without simulating far is how the game stays playable on a wide range of hardware.
What Gets Paused Outside Simulation Distance
The game engine processes world mechanics through a system called “ticks,” running 20 cycles per second. Simulation distance defines which chunks receive those tick updates. Outside that boundary, several things stop completely:
- Mob behavior: All entity AI shuts off. Mobs won’t move, attack, breed, or pathfind. They exist in memory but do nothing.
- Mob spawning: New mobs only spawn within simulation distance. This directly affects mob farms and grinders, since they need to be inside your active radius to produce anything.
- Crop and plant growth: Wheat, carrots, trees, amethyst clusters, and any block that relies on random tick updates will stop growing entirely.
- Fluid movement: Water and lava stop flowing mid-stream if they’re outside the boundary.
Redstone is a partial exception, and it trips people up. Pure redstone circuits (just dust, repeaters, and torches) continue to function regardless of distance. But the moment that circuit interacts with hoppers, pistons, observers, or anything else that needs tick updates, those components freeze. So a redstone clock will keep pulsing, but the piston it’s supposed to activate won’t move if it’s outside simulation distance.
How It Affects Farms and Builds
If you’ve built an automatic crop farm, a mob grinder, or any redstone contraption that interacts with the physical world, it needs to be within your simulation distance to work. This is the single most common reason players find their farms “broken.” The farm is fine. It’s just asleep because you walked too far away.
For mob farms specifically, simulation distance also controls the spawning radius. Setting it too low shrinks the area where hostile mobs can appear, which reduces rates. Setting it higher gives you a larger active spawning zone but also spreads mobs across more chunks, which can dilute the number reaching your kill chamber. Finding the right balance depends on your farm design, but most standard mob farms are built assuming a simulation distance of 4 to 8 chunks.
There’s a subtle extra detail worth knowing. One additional chunk-thick border just outside your simulation distance can still receive some limited processing: redstone, fluid flow, and crop growth may tick there under normal chunk ticking rules. Beyond that single extra ring, nothing moves or changes at all.
Performance Impact
Simulation distance has a much bigger impact on CPU usage than render distance does. Every additional chunk in the simulation radius adds entities to track, blocks to tick, and spawning calculations to run. Render distance mostly loads your GPU with visual data, which modern graphics cards handle efficiently. Simulation distance loads your CPU with logic, and that scales fast, especially in areas dense with mobs or redstone.
On multiplayer servers, this effect multiplies. Each player has their own simulation radius, so five players at simulation distance 10 means the server is actively ticking far more chunks than five players at simulation distance 6. Server administrators commonly run simulation distances of 6 to 8 while keeping render distance at 10 to 12, since that balance keeps the world feeling open without overloading tick processing. One commonly referenced benchmark from a server running similar settings showed stable performance at around 26 milliseconds per tick with five players online, which is close to the 50ms ceiling before the game starts lagging.
If you’re playing single-player on a lower-end machine, dropping simulation distance to 4 is the single most effective change you can make for performance. You’ll barely notice the difference during casual exploration, but your CPU will thank you. Raise it when you’re AFK-ing at a farm and need the surrounding area active.
Bedrock vs. Java Edition
Both editions use simulation distance, but they measure it slightly differently. Bedrock Edition uses taxicab distance (also called Manhattan distance), meaning it measures chunks in a diamond-shaped pattern by counting horizontal and vertical steps rather than straight-line distance. Java Edition uses a square region. The practical difference is that at the same numerical setting, the shape of your active area differs slightly, with Bedrock’s diamond covering fewer total chunks than Java’s square.
Bedrock also exposes simulation distance as an explicit slider in the world settings menu, making it easy to adjust per-world. Java Edition has the setting available in server properties and in singleplayer options, though historically it was tied more closely to render distance before being split into its own control.
Choosing the Right Setting
For general exploration and building, a simulation distance of 4 to 6 chunks works well and keeps performance smooth. You won’t notice mobs freezing in the distance because they’re far enough away to be out of sight anyway, especially if your render distance is higher.
Bump it up to 8 or 10 when you’re running farms or need a larger active area around you. If you’re standing at the center of a complex with multiple farms spread across different chunks, a higher simulation distance ensures they’re all running simultaneously. Just be aware that this costs real CPU headroom, so only raise it when you need it.
On servers, the simulation distance is set globally and applies to all players. If you’re an admin, start at 6 and increase by one chunk at a time while monitoring your milliseconds-per-tick value. Keeping that number under 50ms means the server is running at full speed with no skipped ticks.