Traditionally, client server file traffic has always been considered to be very slow, as compared to file access when the file is placed on Direct Attached Storage (DAS).
Note that clients as used in this particular blog apply to not just clients as in laptops, but also server to server communications where one of the servers acts as a client. For example, a laptop connects across the Internet to an IIS Server, and the IIS Server fetches some files from a file server to satisfy the client request.
Microsoft just posted a white paper showing some very interesting performance benchamrsk for file access over SMB2.2 when both client and server are running Windows 8. The paper can be found here
A one line summary of the paper could be “client/server file access speeds go from high twenty percent to almost parity with speed of Direct Attached Storage” ; and in particular from say 28% to 97%.
Note that the “client” used in the test had 48GB RAM, and while I admit that the test involved non cached I/O, so the extra RAM was not used for caching, it is still worth noting that this is not a typical client as in a laptop client. This is more like a server behaving as a client.
Nevertheless, this makes the client/server world more interesting, and also makes a compelling case for upgrading to Windows 8. Especially so when you can simultaneously upgrade all your servers e.g. SQL, IIS, and NAS file servers to be Windows 8. Upgrading just a single server does not help much, since in that case, the client is still an old client that does not speak the SMB 2.2 protocol.