Sony RX1 has a
24.0MP Full frame (35.8 x 23.8 mm ) sized CMOS sensor . On the other hand, Sony TX100V has a
16.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized BSI-CMOS sensor and features BIONZ processor.
Sony RX1's sensor provides 8MP more than Sony TX100V's sensor, which gives a significant advantage in real life. You can print your images larger or crop more freely.
On the other hand, please keep in mind that Max sensor resolution is not the only determinant of resolving power. Factors such as the optical elements, low pass filter, pixel size and sensor technology also affects the final resolution of the captured image.
Below you can see the RX1 and TX100V sensor size comparison.
As seen above, Sony RX1 has a 30.4x Larger sensor area than Sony TX100V. 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.