Nikon D6 Reference Manual page 1171

Approved Memory Cards
•
The camera can be used with CFexpress (Type B) and XQD
memory cards.
•
Cards with write speeds of 45 MB/s (300×) or better are
recommended for movie recording and playback. Slower
speeds may result in recording being interrupted. Playback
may also be interrupted or jerky when movies are viewed on
the camera.
•
Contact the manufacturer for information on features,
operation, and limitations on use.
Approved Memory Cards
1119