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So this morning I loaded up my work-in-progress Skylands map but then something deeply troubling happened. The allocated memory quickly went up to about 70% and when I moved around a little it reached 100%. I don't remember this happening at all until yesterday when I added a dungeon with a bunch of mob spawners. Also there are still several areas with a flat bottom at Y=64 that I haven't fixed causing lighting glitches. I am convinced that one of those two things is causing this issue, but no matter what is causing it, having to constantly monitor the memory usage and worrying about your game eventually running out of memory would really suck the fun out of the Minecraft experience. I have 1 GB of RAM allocated to Minecraft. Can anyone help me figure this out?

UPDATE 11/9: I found out that this has something to do with the initial large increase in the allocated memory when loading the world. Going to the Nether and back actually lowered the allocated memory amount, so it is definitely something while loading the map.

UPDATE 12/6: I loaded another world of mine first before going on my map, and the allocated memory on the latter never got higher than 37% (384 MB).

UPDATE 12/17: I actually saw the allocated memory at 98% for a second before it hit 100%, which tells me that it is a runaway increase instead of a sudden jump.

UPDATE 1/13/18: I was just on my map and the allocated memory shot up from 35% to 82% in 1 second a little bit after I started digging around in the creative inventory. So I think that has something to do with it.

UPDATE 2/8/18: I have figured out that it has to do with the bed item models (which are in the Decorations tab of the creative menu). Ignore all my other speculation on the cause.

What is a word in this case?

UPDATE: I removed the dungeon I mentioned in the OP from the map and now I am no longer having this problem when loading it.

UPDATE 2: It happened again in another floating dungeon in my map. I think this is mob spawner related because it ALWAYS happens with the floating dungeons in my map.

Quote from allamfsharp»

UPDATE 2: It happened again in another floating dungeon in my map. I think this is mob spawner related because it ALWAYS happens with the floating dungeons in my map.

Upgrade your allocated Ram to minecraft

Okay, this just happened again while I was on my map and I didn't even go near one of the floating dungeons. I am worried that some people might think my map will be dead on arrival because of this.

Quote from allamfsharp»

Okay, this just happened again while I was on my map and I didn't even go near one of the floating dungeons. I am worried that some people might think my map will be dead on arrival because of this.

!!!!!

Quote from Clockpie»

Minecraft can reach 1GB ram easily, especially on large words. Try getting 2GB ram.

World size has no effect on memory usage; I have a world which would require over 6 GB of RAM (nearly twice the amount my computer has in total; 3.2 GB usable out of 4 GB on a 32 bit OS) if it were all loaded at once but the game only uses 200-300 MB out of 512 MB allocated, which is not even fully used either - because only chunks within render distance are loaded (plus the spawn chunks). Age also has no effect; I've spent thousands of hours in the world and even the 500+ tile entities at my main base (in the spawn chunks, so they are always loaded), including chests with millions of resources, have not been an issue.

That aside, a sudden increase in memory usage may point to world corruption; even when I've played around with Superflat presets and created a world made out of mob spawners, the game only lagged severely without maxing out 1 GB of RAM. Of course, mods may change things and it sounds like you are playing modded since vanilla dungeons certainly would not cause any problems (and even here it is because many mods and/or Forge are badly coded; despite all the new features vanilla memory usage has never been increased since early release if not earlier, Mojang sets it to 1 GB for a good reason as too much can slow down performance - and that test was done starting at 512 MB, which already showed a decrease when increased to 1 GB).

Also, what is your render distance, which does play a large role in memory usage since it affects how many chunks are loaded at once. Though vanilla limits it to 16 unless you allocate more than 1 GB so it shouldn't be an issue - unless Optifine still lets you bypass this limit.

My render distance is 7 chunks. The maxing out of the allocated memory doesn't immediately happen as soon as I load the world, rather when I go near a certain area it hits 100% (starts off at 50% and then quickly goes up to 60%) Also my map consists of floating landmasses with around 50 blocks of air below that not including the void. Also I am on vanilla and the floating dungeons were just structures I put into my map.

You guys don't understand the real problem which is that my map shouldn't be taking this much memory! Plus this 100% thing only happens when I don't monitor the memory, when I do it never gets any higher than 67% (on the same map).

Okay, I think I have found the issue. Every single time this happened I had opened the Decorations tab in the creative menu. Just the other day I did that and sure enough the allocated memory went from about 35% to 82% in a fraction of a second, which happens whenever I open that tab in the creative menu.

I am using a downloaded version of Java (1.8.0_121). And I am using NO MODS. This happens only with the Decorations tab (I scrolled all the way through Building Blocks and nothing like this happened). I have 1 GB RAM allocated as I said in the OP (and my JVM arguments are not set in a way that would keep the allocated memory at 100%). The points earlier in the thread where I said it was mob spawners were because it is so easy to jump to conclusions with these things.

I have narrowed it down to having something to do with the bed models. I'm pretty sure this is why the Decorations tab in the creative menu causes the issue, but all the other tabs I checked (namely Building Blocks, Transportation, Redstone, and Miscellaneous) did not cause the issue. Just this morning I crafted a bed in survival and the recipe notification came up showing all 15 other bed models, and sure enough the allocated memory went from 43% to 76% in a second.