How do I get .NET to garbage collect aggressively?

Question

I have an application that is used in image processing, and I find myself typically allocating arrays in the 4000x4000 ushort size, as well as the occasional float and the l

Answer 1

The problem is most likely due to the number of these large objects you have in memory. Fragmentation would be a more likely issue if they are variable sizes (while it could still be an issue.) You stated in the comments that you are storing an undo stack in memory for the image files. If you move this to Disk you would save yourself tons of application memory space.

Also moving the undo to disk should not cause too much of a negative impact on performance because it's not something you will be using all of the time. (If it does become a bottle neck you can always create a hybrid disk/memory cache system.)

Extended...

If you are truly concerned about the possible impact of performance caused by storing undo data on the file system, you may consider that the virtual memory system has a good chance of paging this data to your virtual page file anyway. If you create your own page file/swap space for these undo files, you will have the advantage of being able to control when and where the disk I/O is called. Don't forget, even though we all wish our computers had infinite resources they are very limited.

1.5GB (useable application memory space) / 32MB (large memory request size) ~= 46