OutOfMemoryException when a lot of memory is available

Question

We have an application that is running on 5 (server) nodes (16 cores, 128 GB Memory each) that loads almost 70 GB data on each machine. This application is distributed and serve

Answer 1

Even if there is a memory leak from unmanaged code, if you have 40% memory available you should be able to allocate objects. What I am thinking of is that this is a fragmentation problem not a memory leak.

1- Is the data you are trying to allocate in big or small chunks?

2- Did you try to force the garbage collector (By Calling GC.Collect()) ? garbage collection not only frees memory but compacts it removing fragmentation.