When you profile an assembly, ANTS Memory Profiler analyzes the amount of fragmentation on the Large Object Heap (LOH).

It performs the following calculations to assess whether fragmentation is causing a problem:

Fragmentation ratio = size of the largest empty block on the LOH : total size of all empty blocks on the LOH

Free space ratio = total size of all empty blocks on the LOH : total memory allocated to objects on the LOH

Depending on the result of this calculation, an appropriate message is displayed:

• Memory fragmentation is restricting the size of objects that can be allocated.

  (Displayed in red.)
  The fragmentation ratio is less than 0.3:1.

• Memory fragmentation is affecting the size of the largest object that can be allocated.

  (Displayed in orange.)
  The fragmentation ratio is less than 0.6:1, and greater than 0.3:1.

• Memory fragmentation may be causing .NET to reserve too much free memory.

  (Displayed in red.)
  The free space ratio is greater than 0.7:1, and there are more than three empty blocks over 64k.

• Memory fragmentation may be causing .NET to reserve too much free memory.

  (Displayed in orange.)
  The free space ratio is less than 0.7:1, and greater than 0.4:1, and there are more than three empty blocks over 64k.

• There are many large fragments; fragmentation may become an issue over time.

  (Displayed in black.)
  There are more than ten empty blocks over 64k.