Windows 7: Delay in displaying files in Downloads folder

For a while now I've had an annoying problem when using Windows Explorer under Windows 7 - if I click on My Documents, My Pictures etc. then the files, and their associated icons and chosen details, appear almost instantaneously yet if I click on My Downloads then it takes an age before everything appears even though there are less than 100 files present. This happens both on my desktop and my laptop, which are synced, the data is on a separate partition in each machine and also on different media, HDD in the desktop and SSD in the laptop. Any ideas anybody ? If you need any further information then please ask.