Optimize code

[miso.dca]

Hello,
I have this code

Sub blabla
pocet = Range("B" & Rows.Count).End(xlUp).Row
    For i = 1 To pocet Step 3
        Range("A" & i & ":B" & i).Cut
        ii = i + 1
        Range("F" & ii).Select
        ActiveSheet.Paste
        iii = i + 2
        Range("B" & iii).Cut
        Range("B" & ii).Select
        ActiveSheet.Paste
    Next
End Sub

it works, but it's really slow ... I have more than 1000 rows and this code is really really slow ... it is possible to change it and macro will be faster? thanks for any help !