user: Question: What was the sensor resolution with a minimal CPU usage for a NaturalPoint TrackIR 3 Pro?
Columns: ['Camera', 'Sensor resolution', 'Sensor', 'Output', 'CPU usage', 'IR LEDs']
Types: ['text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Ideal webcam', '640x480', 'monochrome', 'highly compressed', 'small', 'Yes']
SQL:

assistant: SELECT "Sensor resolution" FROM "Table" WHERE "CPU usage" = 'minimal' AND "Camera" = 'NaturalPoint TrackIR 3 Pro';