The operational costs of a mega server will be lower, there is one server to maintain rather than 10, so they will need less people working on that, the fuel bill will be lower, running the hardware in one box uses less than 10 boxes etc etc, its a big reason why companies are moving towards server consolidation now.
The implementation costs will be very high (new hardware and possible infrastructure upgrades). Operational costs is the cost to run and maintain the servers, implementation costs is what it takes to upgrade existing servers or buy new ones.