Code Raider

@Jill S That is exactly why I said do not use MCEdit. It messes up spawning!

@Shi-Ron Morman Make sure you are playing with at least render distance 10 at all times.

That doesn't mean it's not an MCEdit problem. It would be interesting if it wasn't though, as they "fixed" the lc value problem for mobspawning in 1.8.

Without using MCEdit as well? (Just use some world presets.)

If you want to do any test on this issue, please do so on render distance 10 or above, otherwise the test will not show anything about a potential other issue unrelated to the render distance problem.
Also do not use MCEdit for tests with mobspawning, I already had problems with it messing up stuff with the mobspawning. I don't exactly know what the problem with that is (That's most likely a MCEdit problem though).

Everyone having problems rember the one most important rule: Never ever turn the render distance below 10! This will cause this problem for sure. I can't guarantee that it doesn't happen on 10 and above (but that would be a different issue), but it will definitely happen below 10!

Have you tested that in a normal world and just checked your entity count in the F3 screen?

Why not? That is the reason this problem exists.

I can still turn down my render distance below 10, so yes this problem still exists.

I think you don't quite understand how the loaded chunks work. In the two outermost chunks mobs cannot despawn, because they do not receive any updates. Also if you don't have any chunks loaded that are far enough away for them to spawn they will simply not be able to spawn, which is the issue with that.

The problem is that the renderdistance in singleplayer also sets the distance chunks are loaded in, like the viewdistance on servers does.

That is why I said

viewdistance on the server in multiplayer or the renderdistance in singleplayer

This is not what this issue is about. The problem is that mobs cannot despawn and therefore block the mobcap if your viewdistance on the server in multiplayer or the renderdistance in singleplayer is below 9.

This is not related to RAM usage in any way. If you have a view distance of 8 and stand around, you'll soon see no mobs spawning anymore, because most mobs will not be able to despawn.

Exactly, the issue is that the render distance also reduces the range in which the chunks are loaded around the player. And if the loaded chunk distance is less than 9 mobs cannot spawn properly.

Well, only far below you then, right?

I guess you are playing on a server then?

Then this post should be corrected, because as it is now it says that what is causing the bug wouldn't actually be related in any way.
It should describe this bug properly, the actual bug is that a render distance of less than 9 blocks will affect mobspawing as they could only spawn in chunks that are not loaded, or in the two outermost chunks, which means they don't get any updates.
Also this can happen on servers if the chunk loading distance is set below 9 in the server.properties file.
So this means this does not have anything to do with how fast your computer is or anything.

So you say "It's mostly not affected by how many chunks are set to load within video settings." Does that mean you still have that same problem if your chunk loading distance is set to maximum? If so please only test this if your chunk loading distance is set to maximum, because if your chunk loading distance is too low, mobs will not be able to spawn, because either the chunks that are far enough away for mobs to spawn are not loaded, or mobs spawn in the outermost two chunks, which means they get stuck and you don't get to see any mobs spawn.

That only makes it harder to explain the bug, but that doesn't change anything about that we still have the same issue.

What Dinnerbone said on reddit is that the LC value is not supposed to decrease, but that it is a bug that mob spawning is using that value. So actually he confirmed that this is indeed a bug: "That things use this instead of lowest empty chunk (...) should be considered the bug here, which will be fixed."