When you lock the card in MSI Afterburner you override the powerlimit. The powerlimit doesn't effect the powerconsumption at all. It's basically the same thing as using --lock-clock in TBM or with nvidia-smi. All the cards are locked in MSI Afterburner.
TBMiner support setting the powerlimit to. If you set the lock clock to high, the core will trottle. Higher coreclock more heat, more cooling needed, so you want stable clocks, stable fanspeeds.