Infinite computations are not the only computations that are impossible to perform. For example, if I asked you to enumerate (not calculate) the number of X time units in all the time from the start to the end of the universe, setting X to the closest time unit to the time an operation took on your chosen hardware (past, present or future) you would not be able to complete this computation.
For instance, if the fastest hardware available to you performed about one operation each femtosecond, it would not have the time to enumerate all femtoseconds from the birth of the universe to its death. And that number is a finite quantity.
For instance, if the fastest hardware available to you performed about one operation each femtosecond, it would not have the time to enumerate all femtoseconds from the birth of the universe to its death. And that number is a finite quantity.