Both Panasonic GX850 and Ricoh GXR A16 24-85mm have 16.0 MP resolution sensors but Panasonic GX850's sensor is Four Thirds (17.3 x 13 mm ) and Ricoh GXR A16 24-85mm's sensor is APS-C (23.6 x 15.7 mm ).
Since Ricoh GXR A16 24-85mm's has a larger sensor area with the same resolution, this means that it also has a larger pixel area hence better light collecting capacity for a given aperture compared to Panasonic GX850.
Another difference between these two cameras is that Panasonic GX850's sensor lacks anti-alias (Low-Pass) filter. Removing anti-alias filter increases the sharpness and level of detail but at the same time, it increases the chance of moiré occurring in certain scenes.
Below you can see the GX850 and GXR A16 24-85mm F3.5-5.5 sensor size comparison.
As seen above, Ricoh GXR A16 24-85mm has a 1.6x Larger sensor area than Panasonic GX850. Larger sensors give photographer more control on the depth of field and blurry background compared to smaller sensor when shot in same focal length and aperture.