The XB1 has only 768 GCN cores (12 compute units of 64 cores, versus 18 for the PS4), but both CPU and GPU cores are clocked slightly higher than the PS4 (1.75GHz v 1.6 for the CPU, 853MHz v 800 for the GPU).

The PS4P increases everything except the CPU cores count: CPU clock to 2.1GHz, compute units to 36 (hence 2304 cores) and GCN frequency to 911MHz.

The CPU isn't actually very powerful, they use low-power Jaguar cores at 1.6 GHz or so.