DIAGNOSIS No. The RAXE500's internal fan should only spin up audibly under heavy, sustained network load or in a high-temperature environment. Constant loud operation indicates a thermal or firmware issue.
FIX First, ensure proper ventilation. The router needs several inches of clear space on all sides, especially the top and rear vent areas. Do not place it in an enclosed cabinet or on top of other warm electronics. Power cycle the router. If the fan immediately spins loud on a fresh boot in a cool room, it's likely a fault.
IF THAT DIDN'T WORK Check for a firmware update via the web interface (Advanced > Administration > Firmware Update). Some early firmware versions had over-aggressive fan control algorithms. Updating may resolve it.
HEADS UP If the fan noise persists after ensuring good ventilation and updating firmware, contact Netgear support. A constantly loud fan can be a precursor to hardware failure, and the unit may be under warranty.