Found the answer... Unlike my old card, the new one has pre-set min/max range on the GPU and memory for over-clocking. So the Catalyst Control centre no longer needs to test in this range for stability problems. Although, it is advised to keep below 95%.
Above that, the likes of MSI afterburner are required with the safeties disengaged. And in my case (which I am doing) add additional cooling.
(ocultar) Si deseas jugar una partida contra un adversario de nivel similar, puedes definir en tu invitación de nueva partida un rango BKR apropiado a tu interés. En tal caso, nadie con un BKR fuera de dicho rango podrá ver o aceptar la invitación. (Katechka) (mostrar todos los consejos)