Thank you combatking0, ninogenio and Hotshot for your tests. Yes, the DOSBox version is really slow. As far as Win7 goes although the 64-bit version cannot run it, I think the 32-bit version should work fine although requiring a shortcut with compatibility mode enabled and XP version checked.
Again if I don't return before Christmas : Merry Christmas ! (looking forward to those X-Mas compo entries)