The Acer Chromebox CXI has an SSD storage medium which is faster than most personal computers that are a similar age to it. Most comparable spec personal computers that were released more than two years ago have an HDD storage medium. Solid State Drives (SSD) store information in transistors on a circuit board rather than on optical or magnetic media. This has the advantage of being much faster than a traditional HDD drive.
An SSD storage medium is actually the best storage speed amongst all computers of this type and age.
An HDD storage medium is the worst storage speed across similar types of PC.