Fusion Drive is now available in 21.5 inch iMac

According to the information released on the MacRumors Forums and MacGeneration, Apple launches 21.5-inch iMac with integrated 1TB Fusion Drive. Fusion drive, designed for the iMac and Mac mini, combines SSD and traditional hard disk drives into one logical volume.

"With Fusion Drive in your iMac, disk-intensive tasks — from booting up to launching apps to importing photos — are faster and more efficient. That’s because frequently used items are kept at the ready on speedy flash storage, while infrequently accessed items go to the hard drive. The file transfers take place in the background, so you won’t even notice."

Fusion Drive with 1TB is optional, costing $250. Previously this option was offered only on the latest version of 21.5 inch iMac and Mac mini, as well as 27 inch iMacs.