Starting with Google Chrome version 25, your web searches will be automatically encrypted over an HTTPS (Secure Sockets Layer) connection. Until now searches with Chrome were encrypted only if you were logged in to a Google Account. With v25 all searches will now be conducted over HTTPS.
Users are expected to not see any slowdown, but instead should see a speedup due to use of the SPDY protocol.
The change was made to provide users with the more privacy. No longer will "malicious actors" be able to intercept search traffic and trace your search queries.