link you gave me indicates I will be okay with my current wattage (370w when I only need 350w). How long do PSU's last? My old computer is still running with a 350w tier 4 Hiper PSU said:
Common experience of most users. Still, we see an enormous number of failed power supplies in our shop. They last until they fail. If you have a gamer or designer quality computer, you need more power. Amperage is more important than Wattage... Wattage doesn't mean much, really.
What really counts is the ability of the PSU to provide consistent, level output under load. Cheap power supplies simply cannot do that. Their output rises and dips in response to whatever component demands power first... or longest. Most power supplies can provide constant (enough) power for a CPU and fan, hard drive, CD-ROM, Video Graphics port, and USB connections.
But a demanding program such as Photoshop, or CAD, or a game may be too much for many power supplies.
Add a high grade video graphics card, or use a major Gamer motherboard, and you cannot do without a power supply that provides high amperage steadily.
The major failure of a computer power supply, we believe, shows up in pauses and stalls, slow performance, and such. Many computers with inadequate power supplies show their incompetence by shutting down, and then the computer reboots.
It is our believe that many of the problems reported by average users are the result of inadequate or poorly performing power supplies. Hard drives and optical drives also fail when the power supply is erratic.
So asking, how long does a power supply last, is relative to what you mean.
A properly functioning power supply should last three to five years. But poorly functioning PSU's will keep on running, so users think they are fine, even though the computer stalls or slows down.