Photovoltaic (PV) and thermoradiative (TR) devices are power generators that use the radiative energy transfer between a hot and a cold reservoir. For PV devices, the semiconductor at the cold side (PV cell) generates electric power; for TR devices, the semiconductor at the hot side (TR cell) generates electric power. In this work, we compare the performance of the photovoltaic and thermoradiative devices, with and without the non-radiative processes. Without non-radiative processes, PV devices generally produce larger output powers than TR devices. However, when non-radiative processes become important, the TR can outperform the PV devices. This conclusion applies to both far-field and near-field based devices. A key difference in efficiency between PV and TR devices is pointed out.