PSU aging...

[desura]

So I'm a little worried about my PSU.

I loaded my computer up with goodies and on the PSU calculator it says "336"

I have a 400 watt bronze-rated 85 plus PSU from pcpowerparts. The MKIII I think.

So, it is cutting a little close. I've never had it black out on me during load, thankfully.

But...as the electronics age, don't they lose capacity? So could my 400 watt PSU one day shrink to 350 watt?

And...85% of 400 watts is around 330. I"m guessing that if the system ever went to like 350, or 370, while on a 400 watt PSU, there would be problems?

 

[SOFTengCOMPelec]

Best age is achieved by using a good quality brand of PSU, and not going too close to its maximum output rating.
I like to have at least 25 .. 50% more capacity than required, for longevity/reliability and expandability.
E.g. 500 Watt Corsair for a 350 Watt PC. (But I tend to over provision stuff like that).


When a power supply is rated for a particular wattage, e.g. 400 Watts (ignoring some things I will mention later), it means it is rated at up to a maximum of 400 Watts.

The 85% has got nothing to do with that, it would still be 400 Watts.

85% Is referring to the % efficiency, i.e. 85% (or better, mostly) of the energy coming into the power supply, gets converted into up to 400 output watts.

Therefore, more than 400 Watts can be consumed at the supply (mains) socket outlet, to cover the 15% losses. (So call it 470 Watts used from wall socket, or thereabouts N.B. It uses MUCH less than this, it is in proportion to how much OUTPUT is used, and can drop to about 15 watts or less, if your computer is idling, and super low power consumption).

Unfortunately an unbranded or unknown brand, such as pcpowerparts (I've never heard of them), is unlikely to be a good quality PSU.
Poor quality power supplies (unless it was a quality brand, such as Antec, Seasonic, Corsair etc) tend to not be able to cope with even their (sometimes) overly optimistic rating, and tend to only last a relatively short time.

E.g. Months, rather than many years, depending on load. (Longer if rather lighter loaded, usually, but still a bad idea).

As a rule of thumb, if a power supply is very cheap and/or comes with a case (some cases come with good PSU, though, usually very expensive, great branded cases ) and/or feels very light, weak/loose/flexible leads and feels poor quality, then it is usually of poor quality.

The (e.g. 85%) efficiency is complicated, because the exact amount varies with output load, so I won't cover it here.

You can't always achieve the full watts rating, because PSU's usually also have max amp ratings for each of the output supply voltages. E.g. 12 Volt rail(s).

 

[Deders]

I believe as PSU components age, they can still produce the wattage but they just need to draw more from the wall to do so, therefore becoming less efficient.

 

[Meghan54]

I really think this aging worry is overblown, provided you started with good components. True, the parts do age, but if you start with parts like capacitors from Rubycon, Nippon Chemi-Con, Panasonic, Hitachi, et al, vs. crap like CapXon, Teapo....or worse, Su'scon, Canicon or Fuhjyyu, the aging issue is fairly non-existent. However, get a ps with junk for caps, yes, you do have a concern.

 

[lucky9]

Not to mention that if a cheap no-name PSU blows up it can take parts of the hardware hooked to it up to and including the motherboard.