Java using more 100% CPU on macOS/linux

Kamil, my minecraft server on Lunix works well. The client on the macos does not lag, does not hang, everything is fast and healthy. But on MacOS, the processor is 100-300% loaded and the laptop heats up very quickly, and turns off after a while. There are such problems in Windows, otherwise it would have been fixed long ago. I think this is a client problem on MacOS.

1.14.3 pre 2 doesn't address this by the way. 

I still get 1.12.2 and 1.13.2 running without hitting 25% during stress, and fans dont even kick in. 

1.14.3 pre 2 on macbook pro 2016 and imac 2017 and two older linux boxes, and it is 55% and up, rpm of fans blow to 3500 and things are only climbing, activity monitor showing other clients running at 12% 10% 19% 22% .. and 1.14.3 pre 2 at 492% 

It's a clear difference. 

I rather not have the fans on 24/7 for just running a singleplayer session or a server for a friend, or whatever i do in 1.13.2 without any stress to the system. 

BIG TEST: i am in the main menu

18w43a - 19w11b: using 5-10% CPU

19w12a - 1.14-pre3: using 70-110% CPU

this problem appeared 19w12a

1.14.3-pre4 the problem is not fixed

Playing Minecraft on my 13" MacBook Pro without any mods typically drains the battery down from 100% to around 30% after one hour. This is anecdotal, but I don't remember Minecraft using that much battery life before 1.14. I noticed the excessive fan noise as early as the first 1.14 snapshot.

greedino, It is obvious. If the game consumes 200-300% CPU, then naturally the MacBook quickly heats up and discharges. For me, the big problem is that it turns off due to heat during a long game. Hopefully the developers will start working on this issue soon.

I'm on an oldie iMac (2011) playing on Java and 1.14, and it heats up too, mostly on the top part, you couldn't keep your hands on it for too long. It's so hot I have to pause it for a while cause I'm afraid to push it too far.

1.14.4 pre1

Menu: 10-25% CPU
Game: 100-180% CPU 

mb. reopened? 

Yeah, game still gets up to 200% in the larger window, 100% in the smaller one.

UP 1.14.4-pre5 

1.14.4 pre1/pre5 Menu: 10-25% CPU (its god)
1.14.4 pre1/pre5 Game: 100-180% CPU (its not okay)

Still don't know why this hasn't been reopened when it hasn't been fixed. My report even got closed as a duplicate.

The fact that a computer game uses up computing resources when in-game is not a bug.

But after all, in the old versions of the game, everything was fine, and here the problem is regardless of the configuration of the iron.

slicedlime, look up comments 

My MacBook Pro 13 2017: Intel Core i5 7360U (2 x 2.3), Intel Iris Plus Graphics 640, 8gb ram
Comments: MacBook Pro 15 2018: Intel Core i7 8750H (6 x 2.2), Radeon Pro 555X 4gb, 16gb ram

" The fact that a computer game uses up computing resources when in-game is not a bug."

It's not unreasonable to assume as more content is added to the game, the resources required for it will go up. If you are having performance issues, I have some suggestions that come from personal experience:

• Use the FS resolution slider to turn down the resolution (I have a 2015 MBP and run at 720p--great performance). This heavily turns down the amount of resources needed to run the game, since by default it uses the absurdly-high resolution of the retina display (1600p/2100p, much greater than standard 1080p monitors on desktop). Alternatively, there is a good third-party program that will allow you to change the desktop resolution. Look up "Retina Display Manager" (RDM) if you are interested.

• Use the FPS limit slider to turn down the max FPS (I use 60fps max since that is the refresh rate of the laptop). This saves the CPU/GPU from getting unnecessarily overworked doing stuff that will have no benefit.

• [Extra risky option]: I use third-party software to manually set the power of the computer fans. Mac OS seems to prioritize quietness over coolness, so setting the fans to full blast when the computer normally wouldn't could alleviate your heat issues.

@[Helper] Matthew

I do all of that and even then, my 2017 MBP (16 GB Ram) gets too hot to touch above the keyboard, even in 1.14.4 prereleases.

1.14 simply should not be this unoptimised for the mac, to the point that it is unplayable for some users (especially when from 1.13 to 1.14, the official requirements for the game did not change).

@[Helper] Matthew. My settings: 

• Resolution: 640x480

• Graphics: Fast

• Entity Shadows: Off

• Clouds: Off

• Particles: Minimal

• Render Distance: 8

• Max Framerate: 60 

MacBook Pro 13 2017: Intel Core i5 7360U (2 x 2.3), Intel Iris Plus Graphics 640, 8gb ram
using CPU (game): 100-180% (ITS NOT NORMAL) 
using CPU (menu): 10-25% (Mojang tnx for fixing 👍)

Neither the game settings nor the hardware reduces the CPU using. At Christopher Patrtan MacBook is several times more powerful than mine and the problem persists. The problem is not that the game lags, everything works fine at 60 fps. The problem is that the game consumes a lot of CPU resources, the laptop heats up, the cooling does not cope

@[Helper] Matthew

Even with the render distance at 2 chunks it still consistently stays around 80-110% CPU usage, and that's after the 250% when entering the world. That's with all the other settings down like OP has in the comment above. My computer specs are in the bug report I made that was closed as a duplicate of this one, which was made after mine. Still don't entirely get that, but as long as the issue is being taken care of I'm not troubled.

As OP has stated, the problem is the computer heats up; If I put my hand near it, I can feel the hot air being blown out by the fan, which is also very audibly working pretty hard. The cause of this behavior is the abnormal CPU usage. Now, this is not something that was an issue in 1.12, so I'm inclined to believe that this is a bug, introduced somewhere around 1.13.2 from what I've recorded of trying to figure it out.

I find it completely unacceptable that we are being told to do things to mitigate the problem that we've already tried and found to not work. Turning down the render distance does not work. Turning down the resolution does not work. Bringing the graphics settings down does not work. The only thing that works is reverting to a version that does not have the bug.

Even with 640x480, max 60 FPS, render 5 chunks, fast graphics, VSync off, clouds off, particles off, smooth lighting off, entity shadows off, and biome blend off, just standing in a world is ~100% of CPU. Loading the world gets up to 340% CPU. Doing anything (in a world or in menu) is ~50-100% CPU for the launcher as well. That's almost as much as a 300+ modpack in 1.12.2, which is simply unacceptable.

That's just Vanilla 1.14.4 Pre-Release 6 on a 2017 MacBook Pro.

It's the middle of December, 1.15 is out, and guess what's still not fixed? Minecraft eats my CPU, meaning that I can't play it. Mojang, seriously, reopen this.

NOT FIXED 1.15.1

1.15.2 also has the bug.

So, what are we supposed to do now since it's been marked as fixed when it isn't? How do we get this reopened and properly seen to?

PROBLEM SOLVER FOR ME

I used a software nammed cputhrottle (a bit hard to install and to understand) to cap my Minecraft CPU use to 100%, it works better than I expected, i have 60fps Good Quality with Macbook pro 15'' 2018, no overheating, no fan noise. Enjoy !

Hey. Any news on that? I assume that somebody from dev team can reproduce this but anyway I'm attaching a  shapshot of Minecraft in idle mode: 

Alexey, what is it?
p.s I have already scored. No one is going to correct processor consumption on the Mac OS, alas.

> Alexey, what is it?

@Gobbi, it's YourKit CPU snapshot of Minecraft in idle mode (in menu). I guess someone in Mojang should be familiar with such stuff. 

> No one is going to correct processor consumption on the Mac OS, alas.

We shouldn't yield on their ignorance.

Surely they'll get around to it eventually, right? I mean, it'd be a shame to force paying customers to be unable to play past 1.12.2 just by leaving a reported problem unfixed. Certainly they can't have forgotten about us.

Backhanded remarks aside, I'm kinda starting to lose hope, too.

Lurker here, also frustrated with +100% cpu usage from innocuously launching the game with no further interaction, sharing my findings of in-game configuration that resulted in dropping in-play cpu usage down to around 20%, in the hope it helps someone:

MacBook12,1 - 8 GB 2.7 GHz Dual-Core Intel Core i5 running macOS Catalina 10.15.4

Minecraft 1.15.2, Oracle Java Version 8 Update 241, -Xmx1G.
Graphics: Fast; Smooth Lighting: OFF; VSync: ON; Brightness: Moody; Fullscreen: ON; Mipmap Levels: 4; Render Distance: 12 chunks; Max Framerate: 30fps; View Bobbing: OFF; Clouds: OFF; Particles: Minimal; Entity Shadows: OFF.

Dropping the max frame rate afforded the most noticeable benefit, and allocating more than 1GB memory seemed pointless as it anecdotally used no more than 500MB in play.

Can confirm for MacBook Pro 16" Base Model, Late 2019. 20w19a confirmed. Fans running and overheating. This is killing my computer so in the meantime I will be playing 1.8.9. Mojang this is a serious issue for MacOS users - please fix it!

Can confirm for 20w20a & 20w20b. CPU: 1.13.2 - 70%, 1.14 - 400%, 1.15 - 300%

I am a speedrunner but this bug prevents me from speedrunning. This is a HUGE bug; PLEASE FIX IT MOJANG! 

I am not even using a Macbook, i am using a Lenovo Y520 with Windows 10, and i am having this issue as well. Minecraft java CPU usage is passing 100% at sometimes. This was not happening in 1.13.2, also not much happening in 1.14.4 for me. But with 1.15.2 it is happening, and starts to lag my computer when this happens. Would be nice if it is fixed.

I'm not sure if it helps, but I attached a debug report in 20w21a. The game doesn't quite seem to keep up, even after the span of around 5 minutes.

for the meantime, try to set graphics from fancy to fast, minimal particles and clouds off. Also try and turn off other apps in the process

This is insane. I am experiencing 600% CPU from opening an application. The elapsed time on this project is crazy! I cannot play the game anymore! 1.14.4 is the worst. My fans are running like crazy! Mojang please do something about this! We cannot play minecraft like this! Even with the graphics from fancy to fast, minimal particles and clouds off and turning off other apps in the process does not work. Its not a computer issue, but a HUGE BUG THAT NEEDS TO BE FIXED IMMEDIATELY.

I feel like this bug is getting worse and worse. My fans were running at FULL BLAST when I was playing 1.14.4 & 1.15.2. 1.13 is ok, and the snapshots are heating up my computer only slightly above normal. PLEASE FIX, as I can no longer play 1.14 or 1.15! I am sorry that I keep adding comments but the elapsed time on this bug is massive. PLEASE FIX in the latest snapshots and consider adding a "1.14/1.15 NEW" so that we speedrunners are not confined to only 1.13 and 1.16.

I have a iMac, and sometimes, the fan gets really loud. I have a 3.6 GHz Quad-Core Intel Core i3. When I'm playing, a process called java uses up 350% cpu while the game is loading, but about 100% in game, about as much as playing chess against the computer (chess doesn't cause the loud fan noise). I wonder why only Minecraft causes the fan noise.

This happens in 20w27a or not?

This bug is present in Mojave 10.14.6 as well on 1.16 - 1.16.2. Bug came out of nowhere.