Denormalization adds to the volume of data to read and write, and often reduces the global hit ratio of caches.
On most servers the most plentiful and cheap resource is the CPU (not the storage!), and an adequate level of normalization loads CPU while relieving storage.
Normalization often adds storage 'seeks', and therefore doesn't costs much on some storage (SSD...).
Comments
Denormalization adds to the volume of data to read and write, and often reduces the global hit ratio of caches.
On most servers the most plentiful and cheap resource is the CPU (not the storage!), and an adequate level of normalization loads CPU while relieving storage.
Normalization often adds storage 'seeks', and therefore doesn't costs much on some storage (SSD...).