Hi,
I did notice a slight hesitation on my system, but nowhere near 10 seconds, that's for sure. Okay, let's put that aside and try something completly different (it should be fast)...
Code:
For Each Ar In Range("A:C,G:G")
  Riga = Application.Max(Riga, Ar(Ar.Count).End(xlUp).Row)
Next
I tried the last time in a sheet with the cell K625:
Excel 2003 7,9 sec while Excel 2013 4,2 sec Pc New!

Remember that this code should work on a PC 800 mhz...

Thanks for all the suggestions received