(GPU) GTX 1080:
512x512: 0:58.97
full resolution as tile: 1:01.66
256x256: 1:05.13
128x128: 1:17.49
(CPU) r7 1800x - 3.6ghz (8c/16t):
128x128: (estimated) about 1:40 minutes
64x64: (estimated) about 2 minutes
512x512: (estimated) about 12 minutes