C# Large object in medium size collection

Question

I'm pretty new to the memory problem. Hope you don't think this is a stupid question to ask.

I know that memory larger than 85,000 Bytes would be put into LOH in C# i.e.

Byte[] hugeByteCollection = new Byte[85000]; 

I'm wondering if a collection with size 10000 - 20000 with an object that contains 10 member variables (byte type) will be put into LOH or SOH ?

Answer 1

The size of an array of objects is the number of objects times the pointer size. This is because only value types is stored in the array itself, reference types (objects) will be stored somewhere else and will not count towards the size of the array. So 85000/4=21250 objects, and 85000/8=10625 objects can be stored in an array on the SOH in 32bit and 64bit mode, respectively.

Edit: Thanks to Hans Passant for pointing out that this assumes that the collection type used is an array and not a list. Lists resize themselves to be bigger than the content to avoid too many allocations. See this link for details