For manual overclocking, we used MSI Afterburner. We maximised the power target (+105%) and temperature slider (90C), before adding 260MHz to the GPU core and 950MHz to the memory.
This saw average clock speed increase from 1816MHz to 2059MHz, a hefty 13% boost to operating frequency.
This extra frequency resulted in performance gains of between 9-12% in the titles we re-tested at 1080p.
Power only increased by 10W, or 6%, so the overclock proved well worth it.