largest possible in memory array of non integer numbers in C# [duplicate]

Question

Looking at this, it appears that Single is the non integer number with the lowest memory requirements in C#. If I create:

Single[,] data = new Single[100000000, 10];

I am getting a:

System.OutOfMemoryException

Does this depend on my machine's available RAM? Could I keep an array like this or larger in memory? Thanks.

Yes, it depends on your available RAM. You should keep in mind that your array would be the size 40 GB if my calculations are correct. — Mighty Badaboom
– Mighty Badaboom, Commented Apr 5, 2017 at 13:04

nvoigt · Accepted Answer · 2017-04-05 13:15:19Z

3

Does this depend on my machine's available RAM?

To an extent, yes. You cannot have an object that is significantly larger than your memory. However:

Could I keep an array like this or larger in memory?

32bit processes can be 2GB in size maximum (3GB with special exceptions). But even on 64bit systems using a 64bit process, you cannot exceed the size of 2 GB for a single .NET object. So you can have two large arrays of 1.5 GB each, but you could not have a single one of 3 GB. And yours seems to be way above that size.

As commenters pointed out, there is a way around this limit with later editions of .NET:

Put this in your App.config file:

<configuration>  
  <runtime>  
    <gcAllowVeryLargeObjects enabled="true" />  
  </runtime>  
</configuration>

edited Apr 5, 2017 at 13:15

answered Apr 5, 2017 at 13:10

nvoigt

77.7k28 gold badges103 silver badges156 bronze badges

Sign up to request clarification or add additional context in comments.

8 Comments

Evk Over a year ago

Note that article you linked is 12 year old. Now there is a way to allocate objects larger than 2GB.

Matthew Watson Over a year ago

Well, you can use <gcAllowVeryLargeObjects> to allow objects greater than 2GB in size.

nvoigt Over a year ago

@Evk Thanks, added it.

cs0815 Over a year ago

Wow this works for the example. i chose. Bit confused now how, as I definitely do not have 40GB of RAM ... must be magic.

Matthew Watson Over a year ago

@csetzkorn See Virtual memory. Note that just declaring the array only reserves space for it in virtual memory. Only when you start setting values in it will the memory actually be commited. Try initialising it in a loop and watch your program slow to a crawl... ;)

|

Collectives™ on Stack Overflow

largest possible in memory array of non integer numbers in C# [duplicate]

1 Answer 1

8 Comments

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

8 Comments

Linked

Related