There are currently rumors about an upcoming update of the Nvidia GeForce GTX 970M and 980M with the GTX 970MX and 980MX. We have statements from multiple independent sources that have denied these plans.
http://www.notebookcheck.net/Nvidia-No-GTX-970MX-and-980MX-GPUs-in-the-works.158349.0.html
AMD have actually demoed a mobile GPU with many tech sites at GDC already. Most Tech sites are claiming they wouldn't be surprised to see a Polaris Mobile and desktop GPU before mid 2016.
The Mobile (Console performance) Polaris 36W Mobile GPU was demoed against nvidia GTX950 94W desktop GPU (60w Difference).
I honestly believe nvidia are about to get a run for its money spree. :p