Hi Jolivanes,

Thanks for taking the trouble to put that together.

Interestingly I had similar results, albeit about two seconds slower apart from the 'Replace Some' option where it took 41.5 seconds vs your 15.69. Quite considerably longer. And you were correct in your belief that the straightforward
Range("E1:E518401").Replace What:="1", Replacement:="A" construction is more or less the same as option 2.