Refer to figures.
EASA learning objective 022.04.05.01.03 states: 'State the advantages and disadvantages of a remote-reading compass system compared to a direct-reading magnetic compass with regard to: design (power source, weight and volume); deviation due to aircraft magnetism; turning and acceleration errors; attitude errors; accuracy and stability of the information displayed; availability of the information for several systems (compass card, RMI, automatic flight control system (AFCS)).'

A DRMC is a very simple mechanical device mounted in the cockpit of all aircraft which gives an indication of magnetic heading. Due to its location and construction it's prone to deviation caused by the magnetic fields from aircraft avionics, wiring and other magnetic materials nearby.

A RIC is far more complex as it consists of a directional gyroscope which is connected to a flux valve which senses the Earths magnetic field. The RIC system is electrical and contains a synchronising system to keep the gyro correctly aligned and an erection system to keep the gyro spin axis horizontal, it can also pass heading information to other systems. Because the flux valve is usually mounted in remote location, such as the wingtip, it is less affected by deviation caused by aircraft systems.