Why is a SQL Server restore (LOAD DATABASE) so much slower than a dump database?

A. A. The answer to this is that SQL initialises all pages during a load. So if you have 50MB of data in a 5GB database, the dump only processes the used 50MB. But when the load occurs it loads the 50Mb of data - which takes roughly the same time as the dump - and then initialises the rest of the 4.95GB of free space. This initialisation is limited in speed by the performance of the disk subsystem.