According to a detailed analysis of AMD's upcoming GPUs, the new 7 nm Vega 20 might hit the 20 TFLOP barrier. Unfortunately, based on the known specifications of the hardware architecture used, achieving this level of performance would also lead to a high power consumption figure of 400 W.
https://www.notebookcheck.net/AMD-s-upcoming-7-nm-Vega-20-GPU-could-provide-well-above-20-TFLOPs-for-an-insane-TDP-of-over-400-Watt.315958.0.html