I did what agentdark45 (thank you) proposed, cool'n'quiet is the AMD equivalent for speedstep, I dsabled it in bios and the system seems more responsive, I can switch from max while corona renders to other programs so smoothly now, but i only did small region renders I will come back if this doesn't work. but i tell you I don't mind spending a little more in electricity to have a very expensive 64 threads machine that acts like 64 threads!. this cool'nquiet did handicapp my system for a year now. it does feel more fluid.