They did a power analysis on this theory in PC Pro a while back.
A typical modern business desktop draws a lot less power than a tricked-out home PC, and the very low power ones barely any more than a thin client. This difference is offset by the fact that the thin clients need a relatively huge terminal server which is inevitably left running 24/7, where as the desktops can be switched off 2/3rds of the time.
It becomes greener if the power of the server can be utilised 24/7, such as in a multi-national company serving terminals around the world. However, the quality of our Internet does not really permit such application to give a good end-user experience.
When desktops come to the end of their useful life, replacing them with low energy models is preferable. However, replacing good modern machines which are already quite efficient is a false economy. The prime benefit of thin client is ease of administration, rather than energy consumption.
Until our Internet is massively improved the most important green consideration is to simply
switch IT off when not in use.
_________________jonbwfc's law: "In any forum thread someone will, no matter what the subject, mention Firefly."
When you're feeling too silly for x404,
youRwired.net