Few years ago no one seemed to care about the quality of their power supplies, no matter how top notch the rest of the computer system were. This wasn't too wise because a bad PSU can take all the other parts with it in case of failure. Besides having proper protections, a decent PSU also has lower ripple voltage in the output lines, which can, for example, effect the signal quality of the sound card. All together it really is worth paying for the quality.

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