Many thanks for your response, but I think you’ve misunderstood my question.
Irrespective of speed, irrespective of whether it is a hard disk or a solid state disk (as a thunderbolt raid array can come close to speeds of an SSD) what is the difference between working from an internal disk and an external disk when using FCPX?
I’ve read that there’s not point in using a scratch disk with FCPX so I’m wondering what would be wrong with working off the internal SSD and then archiving externally?