Tachikoma said:
Seconded, ideally you want to be aiming for load usage of 75-85% of the maximum capacity of the PSU, depending on the rating (gold, silver, etc), not only are you less likely to have a meltdown, but it's also the sweet spot for maximum efficiency. If you are adding up the power consumption of the various parts, and, for example, getting a figure like 443 watts, you should be buying a 550W or 600W psu, NOT a 450W psu. |
And it's not just about leaving some marging and not forcing the PSU to work at full capacity: PSUs have several output lines and EACH one must meet or exceed the system's corresponding input requirements.