This is the second of a two-part paper on five direct numerical simulations of a differentially heated cavity of aspect ratio 4 with adiabatic horizontal walls (Rayleigh numbers based on the cavity height Ra = 6.4 x 10(8) 2 x 10(9), 10(10), 3 x 10(10) and 10(11), Pr = 0.71). The numerical methods and the time-averaged flow results were presented in the Part I. The heat transfer and the flow dynamics, including the turbulent statistics, the global kinetic energy balances and the internal waves motion phenomenon, are herewith described and discussed. The power-law scalings of the total kinetic dissipation rate and the Nusselt number suggest that a state of transition to a new scaling regime has been reached for the highest Ra. (C) 2009 Elsevier Ltd. All rights reserved.