Sony RX1R has a
24.0MP Full frame (35.8 x 23.9 mm ) sized CMOS sensor . On the other hand, Panasonic FZ1000 II has a
20.0MP 1″ (13.2 x 8.8 mm ) sized BSI-CMOS sensor and features Venus Engine processor.
Another difference between these two cameras is that Sony RX1R'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 RX1R and FZ1000 II sensor size comparison.
As seen above, Sony RX1R has a 7.4x Larger sensor area than Panasonic FZ1000 II. 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.