Hi, this issue I'm talking about is in DNN 4.9.4. 

I always thought that the reason for it is that the editor (and also the filemanager) first tries to read all files in the system before starting (on load).  If in asp.net you have to read a directory which is stuffed with files [ .NET: Directory.getfiles()  ] will just take longer.  (I noticed this during our archiving project)

Advantage: the actual processing of the module is faster,

Disadvantage: it takes a while to read a large folder

Still, if you have this amount of files, it is not really manageable with the filemanager?

My suggestion:

1)      You write your own filemanager for these files (I can write that for you ;-))

2)      Start an archiving project (I guess not all your 1600 files are active?) (and yes I can write that too)

if the 1600 files are in the same folder->yes

If you would have subfolders:

/portals/0/myfiles/2011/12/file20111221_1.pdf.resources
/portals/0/myfiles/2011/12/file20111221_2.pdf.resources
...

I'm guessing the total time for reading everything would be smaller: you will need more calls to get the files per subfolder, but that action would be faster