Performance of DAM is overall slow so we upgraded it to 6.5 latest version and still we are facing the issue of slowness. Please suggest some ways to improve the performance and we are also following all the best practices suggested by Adobe.
First of all check for the unused assets in your site structure and try to keep as many assets that are required for the sites. As most of time we keep on adding the images and videos to DAM and it makes it content heavy.