The Storage Team Blog about file services and storage features in Windows and Windows Server.
A number of third-party blogs are telling people they can speed up Windows Update downloads, and file copy operations, by turning off the Remote Differential Compression (RDC) feature on Windows Vista. This is 100% false. Neither Windows Update or file copy operations use RDC at all.
The RDC feature is simply a DLL that does not consume any system resources, except when you run an application that uses RDC specifically. If you disable RDC, any application that uses it will either not be able to take advantage of RDC or will simply fail. For more information on RDC see this link http://msdn.microsoft.com/en-us/library/aa373254(VS.85).aspx.
I always wonder where people come up with such ridiculous ideas (like the myth about clearing the prefetch folder, or setting it to "5" on XP) - besides, why would MS purposely disable things that would benefit performance in the first place?
Some of those myths are kind of amusing, I think :)