Fix Slow Windows 7 Folder Loading Time
Slow folder loading time in Windows 7? You might experience this for those big-size folders that have a large number of video, photo, document, or audio files. There is a simple way to fix this. First of all, go ahead to the slow loading folder and open its properties window by right-clicking it and select “Properties”. Then, select the “Customize” tab.

Now, if the slow loading folder has mostly documents within, click the drop-down menu under “Optimize this folder for”, select “Documents”, and press “OK”. If the folder contains all the kind of files you can simply select “General Items” from the drop-down menu. Try this simple fix solution and see if you can speed up folder loading time in Windows 7.
Problem: slow folder loading time in Windows 7
Solution: Change the way Windows optimizes the folder
April 7th, 2010 at 8:23 pm
That worked! Now everything is fast >:)
August 24th, 2010 at 11:44 pm
[ALTERNATE SOLUTION]
I had exactly the same problem (slow loading time) for a particular folder (which also happened to be very large) however the above suggestions did not help me.
However I have found an alternate solution!
Try looking in the folder to see if there is an old shortcut which points to a folder that no longer exists.
It seems that sometimes when a folder contains a shortcut to an invalid path, it may take 5-10 seconds for this folder to open. However, if you delete the shortcut, the speed is again instantaneous, even for folders > 20GB.