The MSCOM Team has posted an articles about their migration to a fully x64 environment. It’s an really interesting article.

We began testing the Windows Server x64 Edition of the O/S in early April 2004 with a single “white box” AMD64 reference machine and finally rolled it out across the board for www.microsoft.com at the end of April 2005.

Read the article at source: Microsoft.com Operations : Running Microsoft.com on 64 Bit…The Dependencies, The Goodness, the Gotcha’s.