Everything About [Computers :: PSU]

The most important component!

The Power Supply (PSU) is the single, most important component in ANY computer when it comes 2 stability, reliability, & longevity. The PSU doesn't just kill itself... but you winde up start having to replace ALL your components in a PC. If 1x or more of it's power rails are fluctuating or has spikes or shortages, your components is what eats that! In fact, you usually replace the components long before the PSU finally craps out because it's 'still providing power', but that power is putting everything to the crapper!

A unworthy PSU will use cheap, crap components rated to do things which it can't live up to... it's a sad truth in the lack of responsibility by these companies (almost all from China).

Actual power output & consumption

My APC UPS (Battery BackUp) reports to me that my PC's 600Watt PSU, 19" LCD Monitor, and power-hungry 8800GTS... uses an astounding 300Watts of power under full load (that's not much). The only thing that'd make it eat any more power was if it were SLI/Crossfire (multiple video cards). So no need to get that 1200Watt power supply, unless you just enjoy wasting money!

Now, remembering marketed power ratings, actual power ratings, and then power efficiency... hypothetically, you can say that my PC is using ~300 Watts out of an available 450 Watts provided by my quality 600 Watt P/S while under full load. Full Load does not take into account Peak Power Consumption as it's more of an average then a min/max. Given that any power interruption or "dirty power" can lead to instability, I'd say that I'm sitting with a good lil bit of room to spare.

Assuming that you're going to be using a decent, power-hungry video card... it's safe to say that you want a good, high quality ~500Watt Power Supply for a single Video Card. For SLI, it wouldn't hurt to look at the 600+ Watt PSU with an emphasis on the PLUS (+). Modern video cards especially really can put an immense strain for sure.

Purchasing

My very strong bias: Enermax
Due to long history and excellent track record in server environments where stability is king, but would have no problem getting/trying a couple other manufacturers. In terms of power output: Galaxy > Infinity > Liberty.

If you buy a cheap case (that you think is pretty) w/ a PSU, keep the case... but shelve the PSU or give it to granny! It would be better that you get slower CPU/RAM/etc and a high quality PSU in the long run than fast components at the cost of a poor PSU. Yes, you can probably pick up a "680Watt" PSU for $30 from somewhere if you really wanted to, but do you really want to... NO!!!