In this video, Bjorn Nyland and a co-host use banana boxes to compare the cargo capacity of the 6-seat Tesla Model X to the Model S.
"Model S and X has the same space if 2nd and 3rd row are loaded with cargo. Model X has more space if 2nd row has passengers."
"Jørgen Winther-Larsen and I test the cargo capacity with Model S and Model X. In this test, I used 6 seat configuration Model X. A 7 seat configuration will have less space and therefore be beaten by a Model S if 2nd row are folded/pushed forward."