Sony RX1R has a 24.0MP Full frame (35.8 x 23.9 mm ) sized CMOS sensor . You can shoot at maximum resolution of 6000 x 4000 pixels with aspect ratios of 3:2 and 16:9. RX1R has a native ISO range of 100 - 25600 and it can save files in RAW format which gives you a wider room for post processing.
Sony RX1R is not the highest resolution Full frame camera. Sony A7CR with its 61.0MP sensor is leading in this class. Check the comparison of Sony RX1R vs Sony A7CR or take a look at Highest resolution Compact cameras list.
Sony RX1R DxOMark Sensor Scores
DxOMark is a benchmark that scientifically assesses image quality of camera sensors. Sony RX1R sensor has been tested by DxO Mark and got an overall score of 91 for its image quality. You can find the details of their analysis of Sony RX1R here.
Anti-Aliasing Filter
Another important feature about Sony RX1R's sensor is the lack of anti-alias (Low-pass) filter. Removing anti-aliasing filter increases the sharpness and level of detail but on the other side it also increases the chance of moiré occurring in certain scenes.
Let's look at how the size of the Sony RX1R's Full frame sensor compares with other standard sensor sizes.