NetQoS Performance Center has experienced increasing slowness when loading pages with graphical views.
NPC uses a graphics folder to save temp files of graphics loaded by NPC. These may be retained for a long time. Many files may build up in the directory, especially if an auto-refresh is enabled with many graphical view. This directory is located here:
Windows Server doesn't perform well when the file count gets very high.
Windows Server 2008 R2
If you have a very high file count in this folder, it is safe to delete these .PNG files from the folder. After doing so, you should see a marked performance increase.
We have observed file counts as high as 1.2 million in this folder. NPC views were taking as long as 45-60 seconds to load.