Nintendo will not reveal specs but... Nintendo has never revealed specs of their systems but keep in mind that Nintendo has always come out with a game/demo to demonstrate the capabilities of their respective systems such as 

Super Mario 64 on E3 1996 for the Nintendo 64.

Luigi's Mansion/Super Mario 128 on E3 2001 for the Gamecube.

(Can't find an early tech demo for the Wii).

The bird/zelda demo at E3 2011 for the Wii U.

So Nintendo will most likely have a game/demo that demonstrate capabilities at January 12 or maybe sometime later on the future before the Switch releases. 
