Specifications of ASUS STRIX GTX 1080 Ti have surfaced. The card receives a boost clock of 1708 MHz in OC mode and 1683 MHz in gaming mode. 

Typically you need GPU TWeak software to be active at all times to get that OC mode, so straight out of the box you are looking at that 1683 MHz boost which is considered your default out of the box clocks. The card would get a 1569 MHz default base clock frequency.

The ASUS STRIX GTX 1080 Ti will have its memory clocked at 11100 MHz, again in OC mode. Gaming mode likely just runs the default 11 Gbps. The board is based on a 10+2 phase design and receives two 8-pin power connectors. It looks like the fact that the 1080 Ti will be available ‘early April’.

ASUS STRIX GTX 1080 Ti gets 1683 MHz boost clock