copy/paste values to another set of cells and then operate on the data?

In memory ops are almost always faster than spreadsheet ops.

Sub SheetOp()
   Dim StartTime As Double
   Dim Counter As Long
   StartTime = Timer
   For Counter = 1 To 10000
       Cells(Counter, 1).Value = Cells(Counter, 1).Value + 1
   Next
   MsgBox Timer - StartTime
End Sub

Sub MemoryOp()
   Dim StartTime As Double
   Dim Counter As Long
   Dim Arr As Variant
   StartTime = Timer
   Arr = Range("A1:A10000").Value
   For Counter = 1 To 10000
       Arr(Counter, 1) = Arr(Counter, 1) + 1
   Next
   Range("A1:A10000").Value = Arr
   MsgBox Timer - StartTime
End Sub