Problem with complex form. After closing the form, the RAM will not be

Hello to all.

I have a complicated Windows C# form, when users want to execute that form, it takes up about 1.2 GB of ram.

After closing the form, the ROM will not be empty. this form opened inside of the DEVExpress form. and if user wants to open that form again, this time ram will takes 2.4 Gig of ram And gradually the memory fills up and the memory shortage error is displayed.

If it is passable please help to solve this problem.

how I can clear the RAM when form is closed.

I used Dispose Method. but it does not works.

Best regards.