While running Process Monitor on my primary workstation, I noticed repetitive registry operations coming from Citrix Receiver application on the same keys: 
How repetitive? 13,000+ registry operations per minute on my idle workstation with no active Citrix connections: 
This applies to the Windows 7 client. I don’t see the same activity for the Windows XP client.
I recalled a reading in the Windows Internals 5th Edition:
“Because the registry implements the RegNotifyChangeKey function that applications can use to request notification of registry changes without polling for them, when you launch Process Monitor on a system that’s idle you should not see repetitive accesses to the same registry keys or values. Any such activity identifies a poorly written application that unnecessarily affects a system’s overall performance.”
I don’t know the internals of the Receiver application, but this leaves me wondering if there is some room for improvement by implementing RegNotifyChangeKey to make it less “noisy”.
Windows Explored 