Power Supplies, as all electrical components have a certain lifespan. As time passes by, a PSU loses its initial power. Also, the majority of PSU failures is from aging Capacitors. I will not lie to you, I love Cooler Master cases and their CPU coolers, but PSUs is not something Cooler Master is great at. The unit you have is from the more "acceptable" ones. But since it is over 5 years, I strongly suggest a replacement.