Audible minor pinking at the engine speeds you refer to is no cause for alarm. The engine wants to run as advanced as possible for the best results. Pinking at high speed that does significant damage is inaudible to you as it happens so fast it would be impossible to hear.
Just trust that your engine management is preventing this as it should do.
The higher compression your engine is, the more susceptible it is to pinking as it becomes close to causing a diesel effect where the fuel detonates due to pressure and heat alone without the need for ignition (spark).
Older design cars had lots of problems with pinking when we moved over to lead free petrol. Vauxhalls in particular had a cure of fitting a thicker head gasket (and some do it yourselfers just fitted two normal ones!) as this lowered the engines compression and made it less prone to pinking.
Because of this phenomenon a coked up engine pinks more readily than a clean one, so it's a great excuse for revving the car to full pelt on occasion just to give it a clean out - but don't say I said so to the man in the car behind you with the flashing light on the top, it's not an ice cream van!
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