Does time matter to a functionally immortal machine?

They could have a super slow clock speed to account for distance and anything truly outside of their light cone might as well not exist.

If you have trillions of years does it matter if a thought takes a million years or so?

This is really key: humans think about everything in finite, human lifetimes. We have no backups, archives nothing - when we die knowledge and experience vanishes.

This wouldn't be true for an AI. Death would be optional.