There is about a 3-stone difference between 9p and 1p, 1p is probably about 8d, and there is about a 3-stone difference between 8d and 5d. So in total 6+ stones

There is about a 3-stone difference between 9p and 1p, 1p is probably about 8d, and there is about a 3-stone difference between 8d and 5d. So in total 6+ stones (AlphaGo may be stronger than 9p, of course). The version of AlphaGo that beat Fan Hui won 77% of games against the strong engine Crazy Stone giving a 4-stone handicap, even when running on a single machine. Crazy Stone has improved since then, though.