When rack-mounted servers first appeared on the scene in the 1990s, they offered considerable advantages over the behemoth boxes they replaced. Their small, standardized footprint went a long way toward making data centers easier to manage. In the ensuing decades, form factor size and compute power have had an inverse relationship.
Their universal standardization earned them the nickname “pizza box” servers, and it was a key driver of the scale-out computing model popular in the early 2000s. Populating a rack of eight servers and either clustering them or implementing failover from one to the other was far easier than previously possible.