Nikon D4s is showcased by Nikon in current CES 2014 show, the Nikon D4s will features
1. Same sensor as Nikon D4
2. Advance Image Processor
3. New AF system
4. same memory card configuration as the D4: one XQD and one CF slots.
The D4s is a next gen camera from Nikon and features a decent upgrade over Nikon D4, however the sensor remains same and so the image quality.
source – NR.com