The Importance of RAM in AI

The more data that you have on the RAM, the more RAM you have, the faster your processing becomes. But at the same time, we have to remember as well that the disk right now are moving to solid state disk,. And how much difference does it have compared to this? I have not studied Micron myself and I have not invested in it. Right now SSDs are getting as fast as the RAM nowadays. So do we really need the RAM, which is super fast and so on?