Few possibilities -
1. GTX 1070. Full desktop version. One issue - "We are not allowed to reveal specs". 1070 specs are already public.
2. 480X. Full desktop version.
3. 1080M. Like all x80M, this needs to have a 100W TDP. Unless GP104 is a Fiji like case where they are pushing way outside the optimal clock speed / W ratio, I don't see this performance in 100W happening. Has anyone done underclocking/volting tests on 1080?
4. M490 CF.
Edit - So, I missed the old GXXX label. Probably a 1070 then, or that could be the model number of the laptop.