Normal
Heat will transfer faster to your hand than to the surrounding air. If you want to get a better qualitative idea of how much heat the power supply dissipates into your case, try taking the PSU out such that it's far away from other powerful components and hold your hand near it without touching the casing. That heat is dissipated through radiation and convection, and there will be very little of it. The rest is exhausted out through the back.It is unlikely that your power supply is dissipating a lot of heat to your enclosure, unless if its exhaust is being used by other components. Most cases around 4 liters in size orient the PSU such that it exhausts air out of the back. Instead of adding an 80 mm fan to the top or bottom, which might even cause more heat to flow back into the case, I would suggest adding an extra 40 mm fan with a wire grill/ finger guard to the back if you really want to improve airflow.
Heat will transfer faster to your hand than to the surrounding air. If you want to get a better qualitative idea of how much heat the power supply dissipates into your case, try taking the PSU out such that it's far away from other powerful components and hold your hand near it without touching the casing. That heat is dissipated through radiation and convection, and there will be very little of it. The rest is exhausted out through the back.
It is unlikely that your power supply is dissipating a lot of heat to your enclosure, unless if its exhaust is being used by other components. Most cases around 4 liters in size orient the PSU such that it exhausts air out of the back. Instead of adding an 80 mm fan to the top or bottom, which might even cause more heat to flow back into the case, I would suggest adding an extra 40 mm fan with a wire grill/ finger guard to the back if you really want to improve airflow.
