Run at stock as your gpu is overheating.benchmarks have different setup from us
I'll just show you the temps and speeds off of GPUZ:
GPU Core Clock [MHz] , GPU Memory Clock [MHz] , GPU Temperature [°C] , Fan Speed (%) [%], GPU Load [%]
925.0 1500.0 69.0 36 78
1130.0 1580.0 67.0 36 43
Those are from my last two black screens, nothing seems odd to me there.