Minecraft running out of memory.

[dracco4heads]

Hello there, i have resently been haveing problems with minecraft running out of memory, crashing my server, and comeing up with this message.
Out of memory!
Minecraft has run out of memory.

This could be caused by a bug in the game or by the Java Virtual Machine not being allocated enough memory. If you are playing in a web browser, try downloading the game and playing it offline.

To prevent level corruption, the current game has quit.

Please restart the game.

Further more, when this message shows, i can not close minecraft, the only way i can close it (or open it again for that sake) is by entirely rebooting the system. I am not playing in a browser ofc.
Also when i press f3, the allocated memory never goes above 50%
I tried reinstalling minecraft, but that did not help.

[Profyrion]

You never have to reboot from this kind of crash. Alt+F4 or Ctrl+Alt+Del and use the Task Manager to recover the system.

There are ways to allocate additional memory (and processor cores) to certain applications, but you'll want to do a little Googling and reading on your own for that. Reinstalling will likely never fix this type of error, as it has more to do with the way Windows gives resources to the program.

How much physical memory (RAM) do you have?

[b00rz]

What version of Java are you using? Minecraft runs better on 64bit Java but obv if your running 32 bit windows ignore me

[Deleted]

Try switching Java versions. In case you got a 64 bit system try Java 7 64bit, otherwise Java 7 32bit.

Also in case this error happens just kill the javaw.exe process (this is your "actual" minecraft-process) in your task-manager, no rebooting required.

Furthermore: in case you start MC by using the minecraft.exe try switching over to using the .jar file to start it up (via a batch-file). That way you can fiddle around with the parameters (allocating RAM and such) with can help a ton.
(edit: You get the .jar from http://www.minecraft.net/download by clicking on "Show all platforms" -> "Minecraft for Linux / Other"; this is an alternative Launcher - NOT to be confused with the .jar file in your bin-directory [the one you mod or HD-patch etc.])

Still after all that, I kept having that problem (but performance was already better). What really did it for me was fiddling with my nVIDIA settings: Go there and change your settings for javaw.exe only (add it to the list). I enabled 3x buffer, threaded optimising and vsync and voilà... never had that pesky error again. Plus less CPU workload.

[PizzaSHARK]

Launch Minecraft using the new Magic Launcher tool. You can then use it to easily customize how much memory is allocated to Java (read: Minecraft) through Setup -> Advanced. My system has 2GB of RAM and I run Minecraft with 512MB of memory allocated and never have issues. Minecraft generally should not ever need more than 1024MB (1GB) of memory allocated to it, and most of the time you'll be fine with only 256MB allocated to it. The only time I ran into issues was when I was flying along at maximum speed (something like 1 chunk per second) and the game was trying to keep up with having to load a skillion chunks at once. Boosting it up to 512MB eliminated that problem.

By default, Minecraft is set to use 1024MB of memory, which is actually a lot more than it needs.

[Grokal]

My minecraft has periods of time where it can sometimes glitch out and crash because of memory like six times in a row, to fix it I normally just have to close everything else so MC has more space to run by itself rather than share RAM, my video card can be the same way when I have games like WoW up while MC is up, together they tend to crash and require it to recover depending on what I'm doing and how high I keep the settings.