Minecraft Forums

Hi everyone!

I have a problem with minecraft

umm..
I want allocate more ram for minecraft but i can't

I have 4 GB ram
And my operating system ; 64-bit
My free ram: 2148 MB

I want allocate 2GB ram but if i tried this; ( -Xmx2G ) on launcher

I got that problem ;

"error occured during initialization of VM could not reserve enough space for 2097152KB object heap"

But if i do Xmx-1G its works

What should i do ? upgrade ram ? or can i solve this problem with 4 gb ram ?

I hope i can explained it

Sorry for my bad english

Thanks for your helps

Minecraft uses double what you assign in -Xmx, so -Xmx2G would try to use at max 4gb. you dont have that much free RAM(2048 is 2G, you have 2148mb) so it crashes saying that it cannot reserver enough for the heap

Quote from urielsalis»

Minecraft uses double what you assign in -Xmx, so -Xmx2G would try to use at max 4gb. you dont have that much free RAM(2048 is 2G, you have 2148mb) so it crashes saying that it cannot reserver enough for the heap

Whaaaaaaaaaaaat?
No. The problem is that the OP is using 32bit Java. You must use 64bit Java to support a process size over 2G, which you hit with a heap size of somewhere around 1.5G since the heap is only a part of the total process size.

Quote from gerbil»

Whaaaaaaaaaaaat?
No. The problem is that the OP is using 32bit Java. You must use 64bit Java to support a process size over 2G, which you hit with a heap size of somewhere around 1.5G since the heap is only a part of the total process size.

The java heap is separated from -Xmx, and is aprox the same as what you allocate using -Xmx, so you basically need double what you are allocating to be safe, not saying that is not one of the causes too

Quote from gerbil»

Whaaaaaaaaaaaat?
No. The problem is that the OP is using 32bit Java. You must use 64bit Java to support a process size over 2G, which you hit with a heap size of somewhere around 1.5G since the heap is only a part of the total process size.

OMG!!! YES IT WORKS!

i installed java (64 bit) and i can allocate 3G ram now !
i got higher and smooth fps

Gerbil Thank you bro / sis
you really did good job

sorry for my bad english again and umm..
I don't know how can i very very many thanks to you in english


And urielsalis

Thanks for your care and help

Glad it works!

Quote from urielsalis»

The java heap is separated from -Xmx, and is aprox the same as what you allocate using -Xmx, so you basically need double what you are allocating to be safe, not saying that is not one of the causes too

Quote from Java documentation

-Xmx

This option sets the maximum Java heap size. The Java heap (the “heap”)
is the part of the memory where blocks of memory are allocated to
objects and freed during garbage collection. Depending upon the kind of
operating system you are running, the maximum value you can set for the
Java heap can vary.

Oh wow sorry, I got it confused with another thing, sorry. Correct formula was

Max memory = [-Xmx] + [-XX:MaxPermSize] + number_of_threads * [-Xss]



+ some extra for GC, JIT optimization, Off-heap allocations, JNI code(some of lwjgl stuff for example), Metaspace



The recommendation was to allocate half, to account for all that, sorry