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.
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