Computers with Small Capacity SSD - For caching?

Question

Recently, in newsletters from websites, I have been seeing computers for sale from manufacturers that include an HDD and an SSD but the SSD has a small capacity like 24 GBs.

I don't know if this still holds true, but I learned that when building a computer, you would want to install your OS on your fastest hard drive. I do a lot of PC gaming, so I install my OS and games on my SSD, because I learned that games and many applications make lots of system calls to the OS and performance can only be as fast as the slowest piece.

Why these computers come with small capacity SSDs?

Most OS's take up around 20 to 30 GBs of space, so what are the benefits of such a small SSD?

Are these small size SSDs for caching? and what exactly does caching mean (what does it do and how does it help)?

Answer 1

That's correct, the SSDs are used for caching. In the simplest implementations, the most frequently accessed information and information that is loaded at system startup is kept on the SSD. In more sophisticated implementations, the SSD can be used as a write cache, to prevent writes to the hard disk from excessively delaying reads from the hard disk by allowing the writes to be buffered to the SSD.