If you’re building a new PVR or HTPC, it can difficult to pick the right wattage for your power supply (PUS). You don’t want it too high because this costs extra money and noise. But you certainly don’t want it too low because this can result in many different problems.
This tools will help you out.
It allows you to enter every little detail about the system you are building and it will calculate how much watt your PSU should deliver. You can enter the type of motherboard, how many drives, video card, etc.