What's an SSD and does it help speed up a Mac?
SSD short for Solid State Drive is a recent evolution in hard drive technology. SSD's have many advantages over a conventional platter-based hard disk:


Improved read and write speeds: A typical SSD is multiple factors of times faster than a magnetic hard disk. This results in a much higher read and write speeds leading to faster overall user experience.
Much lesser chances of failure: There are close to no moving parts in SSD. SSDs is basically just an integrated circuit. This greatly reduces any chance of failure due to movement while in operation (common in traditional hard drive).
Unaffected by magnetic field interferences: SSDs are generally not susceptible to failure (compared to traditional platter-based drives) due to exposure to magnetic fields as there are no magnetic parts present. The core technology doesn't use magnetic state to store data.
Silent operation: SSDs are also dead silent while in operation.
Consume less power: Due to the absence of moving parts, SSDs consume much less power. Helpful when you are using a portable computer on battery power.


Since a hard drive's read/write speed is generally a major bottleneck in the overall performance of a computer system, it is recommended to upgrade to an SSD (if your computer supports it) to improve performance.

Mac minis were conventionally shipped without an SSD, so many recommend to replace the internal drive with a compatible SSD to see improved performance, especially when using data-intensive applications. Faster read-write also speeds up paging performance, thereby improving system responsiveness.

The current generation of Mac mini can be configured with an SSD while placing an order.