1sockchuck writes: The largest cloud builders now pump at least $1 billion into each of their new data center campuses, and may invest as much as $5 billion in future projects. This week Data Center Frontier profiles the top 10 cloud campuses, which feature massive investments in Virginia by Microsoft ($1.7 billion), Digital Realty ($1.3 billion) and DuPont Fabros ($1.2 billion). The NSA, Google and Apple have all spent in excess of $1 billion on their largest campuses. The top-ranked cloud campus is the Switch SUPERNAP project in Las Vegas, which has grown to 1.4 million square feet over three data centers. Switch has announced plans to spend $5 billion to convert an odd pyramid-shaped office building in Michigan into a data center, and has broken ground on a massive Reno project that kicks off with a single building with 1 million square feet of space.