Is it worse to torture a virtual person running on redundant hardware (say 3 computers in lock-step, like the Space Shuttle used) whose permanent state (or backups) is stored on a RAID1 of disks instead of a virtual person running on a single CPU with one disk? Or even simpler; is it worse to torture a more massive person than a less massive person? Personally, I would say no.

Just like there's only one electron, I think there's only one of any particular thing, at least in the map. The territory may actually be weird and strange, but I don't have any evidence that redundant exact copies have as much moral weight as a single entity. I think that it's worse to torture 1 non-redundant person than it is to torture n-1 out of n exact copies of that person, for any n. That only applies if it's exactly the same simulation n-1 times. If those simulations start to diverge into n different persons, it starts to become as bad as torturing n different unique people. Eventually even those n-1 exact copies would diverge enough from the original to be considered copies of a different person with its own moral weight. My reasoning is just probabilistic in expected utility: It's worse for an agent to expect p(torture)=1 than p(torture)=n-1/n, and an identical agent can't distinguish between identical copies (including its environment) of itself.