If you are changing components in your computer like your processor or video card, you might need a new power supply unit, also known as (PSU). Quad core processors consume more than its dual core counterparts and if your power supply was close to its maximum output then your computer will shut down. Desktop computer vendors equip their computers with a PSU that has a little bit more Wattage than what it consumes in order to maximize profit. So making any change in its components or adding new ones could result in your computer behaving in the following ways:

- Spontaneous resets or unexpected shutdowns of the PC
- Bad 3d performance
- Games and applications crashing or closing
- Freezes during gameplay
- Lastly, PSU overload leading to break down of the PSU in some cases

In my case, I had a 500 watts power supply and I exceeded the 80% mark of total power. PSU’s although they state 500 watts of power, you will never use that amount since part of it is lost in heat. So most PSU’s are around 80% efficient, exceeding that mark can cause it to malfunction or break down. My old computer had no ventilation of any kind, inside it was hot, adding this to the fact that I had exceeded the 80 % mark, caused, in my own theory, a capacitor to malfunction making a highly annoying high pitch noise. The PSU did not break down, but I am pretty sure it was getting there so I had my PSU replaced with a higher Wattage one and greatly improved cooling. This occurred when the computer was being stressed out, since this is the moment where components consume the most.

Watts is not the only thing to take into account; you also need to check the Amperage in the +12 volts connections if you plan to use or buy a video card. How to check the Amperage and Wattage of your PSU?

Power supplies have a chart printed in the retail box and a sticker in the actual power supply: