Questions:

1. What OS you are running? 32bit? 64bit?
If your OS is 32bit OS, then no matter how much memory in your machine,
your application just can use 2G/3G memory (except your application uses
PAE in some special OS).

Hence, if you just run a 32bit application and it requires more than
2G/3G memory, no matter Dotnet or native , it will be out of memory.

2. What is the Dotnet version? 1.x, 2.0 or above?
if you are running dotnet1.x application, even running in 64bit OS, it
just will run in 32bit mode. It still cannot use more than 2G memory.

Of cause, it is possible your application has bug or you catch some
system bug to cause the OutOfMemoryException.