http://videocardz.com/59558/nvidia-geforce-gtx-1080-3dmark-benchmarks
The second benchmark we have is from FireStrike Extreme, which as you probably already know is rendered at 2560×1440 resolution. This is actually the first benchmark where you will see 1.860 GHz clock. In this scenario GTX 1080 is faster than typical overclocked GTX 980 Ti (~8700 points). However if we compare it GTX 980 Ti running at almost the same frequency (1.8GHz with LN2 cooling), GTX 1080 is actually much slower clock to clock (link).

