# Does player movement speed up mob spawners?

I have a friend that claims the faster you move around a mob spawner, the faster the mobs spawn. He likes to build powered rails near the spawner and ride a minecart in a loop. This is to increase the spawn rate, supposedly to several times as fast.

I was unable to find any credible source that mentions this. Is this in fact true, or is he misguided?

• Moving the player does make you feel time going faster, though... – Alvin Wong Jun 21 '13 at 15:02
• @AlvinWong Right, because "a watched pot never boils", maybe not waiting on the spawner just seems to speed it up. – Kendall Frey Jun 21 '13 at 15:09

I would say misguided. Check out the algorithm provided by the Minecraft wiki:

``````every spawn cycle (every randInt(200,799) ticks when a player is within
17 blocks of the spawner),
loop 4 times {
if there are 6 or more of the mob type in the 17x9x17 area around the spawner,
skip this spawn cycle
calculate spawnerX = X coordinate of center of spawner - 0.5
calculate spawnerY = Y coordinate of center of spawner - 0.5
calculate spawnerZ = Z coordinate of center of spawner - 0.5
calculate x coordinate of mob = spawnerX + (randDouble() - randDouble()) * 4,
randDouble being a random number between 0 and 1
calculate y coordinate of mob = spawnerY + a random integer between -1 and 1
calculate z coordinate of mob = spawnerZ + (randDouble() - randDouble()) * 4,
randDouble being a random number between 0 and 1
if all of the conditions specific to the mob type are met, spawn the mob {
chicken, cow, mooshroom, pig, sheep, wolf:
block below spawning block is grass
spawning block has a light level of 9 or higher

ocelot:
pass a 2/3 random test
block below spawning block is grass or leaves
on layer 63 or higher

creeper, enderman, skeleton, spider, cave spider, zombie:
light level 7 or less

blaze:
light level 11 or less

silverfish:
light level 11 or less, or on Stone blocks
no players within 5 blocks

slime:
difficulty is not set to peaceful or slime size is small
either:
spawn block y coordinate is less than 40
the chunk containing the spawn block is a slime chunk (1 in 10 chance)
pass a 1 in 10 random test
or:
swamp biome, layer 51 through 69, light level 7 or less

ghast:
pass a 1 in 20 random test

squid:
must not collide with any other entities
must be in layer 46-62

giant:
light level 7 or less
light level 8 or more
(since these conditions can't be true simultaneously, giant spawners don't work)

all except squid and slimes:
must not collide with any blocks or other entities
must not collide with water or lava
}
}
if all 4 mobs failed to spawn, repeat on the next tick
``````

Note that it has nothing about player speed in it.

• This is all good and well, but there might be a bug or feature in there that the faster the player walks the faster the game cycle runs? – Lyrion Jun 21 '13 at 11:33
• What if movement is going in and out of the 17 block radius? Does it re-set the spawn cycle timer? – Batophobia Jun 21 '13 at 14:33
• @Lyrion - I'm fairly certain that the game cycle does not depend, in any way, on player speed. That would imply that running makes the day-night cycle go faster. – Turtleweezard Jun 27 '13 at 20:43
• @DavidStarkey This is the relevant line in the algorithm above "every spawn cycle (every randInt(200,799) ticks when a player is within 17 blocks of the spawner)," The question is, how is the spawn cycle affected by player movement in/out of the 17 block radius. – John Jul 3 '13 at 19:44
• @John, It's more out of my curiosity. I've extended it into a new question – Batophobia Jul 3 '13 at 19:53

Spawners do not depend on player travel rates when spawning mobs. They have meta information attached to them which decides the rate of spawning, player distance, and so on.

If you wish to modify those properties, you would need an external map editing tool such as MCEdit, along with a filter able to edit spawners.

Not player speed but player vicinity does make a difference.

If you move outside of a block (I forget the exact distances, its either a 32 block radius or 128 block!!) the spawner won't be active at all.

Once you are in the vicinity though it makes no difference how fast you move about.

I'm unsure if lighting up the area around the spawner increases spawn rate but in theory if mobs are not spawning elsewhere it makes sense the spawner would pump out more. They may not work like this though.

I'm not sure where the 17 block radius thing comes from in the wiki, I have farmed spawners stood much further away. 17 may be out of date.

• I have never seen a spawner spawn a creature when I am more than 17 blocks away. Can you provide some more evidence of this? Which spawner? How far can you go and still have it active? – John Jun 21 '13 at 18:17
• I'm fairly certain when he says 17 blocks he's talking about spawners using actual mob spawner blocks, not designs based on dark rooms and natural mob spawning. – user68851 Feb 9 '14 at 9:16

I doubt that you would be able to make them spawn faster, but I'm sure if you light up the different areas where hostile mobs could spawn (way harder than it sounds) the rates should be a lot faster unless you're using a dungeon spawner instead of a "honeycomb" spawner. If you're using a honey comb spawner, you can depict which mobs can spawn by using a variety of slabs and trap doors to accommodate their hitboxes. I.e. a spider needs a total area of 9x1 blocks to spawn while a zombie and a skeleton need a 1x2 area to spawn. Silverfish needs 1x1 to spawn, endermen need 3x1 to spawn, etc.