Simple!

I suppose I could have used this as a ‘What is it?’, but anyone who has carried out this task would soon guess. My Mac now has twice as much memory as it had, so its performance should be better. Not that it was a problem, but I thought I might as well use the empty storage spaces.

It was a little scary, but not as scary as last time when a screwdriver was involved. No screwdriver required today.Open the memory compartment door, use the levers to release the memory cage, slot in the memory modules and close it all up. Simple!