look how much power computers use

[ecet]

500 watt power supplies seem like overkill

http://www.silentpcreview.com/article265-page1.html

...

[ZenOps]

You have to factor in that they mostly measured at each of the devices and not from the wall socket.

A PSU is around 60 to 70 percent efficient, when in converts from household current to 12, 5 or 3.3 volts - you lose a lot of electricity in the conversion to heat.

I dare you to try running any modern computer on a 250 watt powersupply, It most likely will not turn on, or will quickly trip the overload circuit (or if you are unlucky, it can fry the computer)

I have an APC Back-ups HS which measures Wattage from the wall socket (to an accuracy of 2 watts) My Pentium 3.2C with Radeon 9800pro AIW, 1GB, 1HD, 1DVD draws 225watts when running 3D games (DVD and floppy inactive)

SPCR's results are far too low, perhaps they have their kill-a-watt set for Europe UK voltage settings (220? instead of 110?)

[Cafe_333]

SPCR is a north american website and a respected one at that - what's not to believe about their numbers? I'm sure their voltage settings were all set correctly as they often do lots of power measurements in their reviews. I believe their numbers are accurate and that's all it really takes to power every system's component provided they can actually get that raw amount from the power supply. I've also read other articles supporting the same results that modern systems do not even draw out 300W. I will at least agree that you are correct in saying that many power supplies are not 100% efficient - and this includes some of the name brands out there. Especially more true on the generics. So a good quality power supply that's tried and true which can push out all voltages on every line like it's supposed to is all you really need. Of course it's always a good idea to get a little more than required - but anything 500W and up I would say is seriously overkill for a typical modern system. ;)

[ZenOps]

SPCR mainly reviews products that are ultrahigh efficiency, low noise, and low heat producing.

The average joe-blows computer with a 65 percent efficient powersupply, non-Asus (3 phase power) motherboard, generic main ram (.25 micron possibly), and minimum 80 watt Intel or AMD CPU at load (confirmed by Intel and AMD themselves with their datasheets) will never see under 150 watts of usage in most cases.

I'm an Intel IPD/ITP/Microsoft OEM system builder, trust me.

BTW: for reference, although Antec Truepower/smartpower makes some of the highest quality PSU's, they are some of the worst for overall efficiency at 68 percent. The Seasonics that SPCR tend to use are rated for 80 percent efficiency, sometimes up to 85 percent at half load.

That makes a huge difference in overall power consumption.

[goofball]

while I hold SPCR in high regards, they do mention at the end that it is not a definitive article and that there are more things to consider. Voltage regulation is a very big one.

Having read that article, it is very informative but I have had some experiences with good PSU's and overclocking that can bring an ATX 2.0 PSU with dual +12v rails down and out for the count. This is with a Forton BlueStorm 500w, so it is not a cheap PSU that I was being used either. The unit was deemed not faulty but just because of the split rail design, unable to put out enough amperage on +12v1 to power the system adequately. Subsequently, a Powerstream 520w was installed and it worked fine.

As already mentioned, very good article but should not be considered the "definitive guide" to base PSU purchasing decisions on.

[ZenOps]

I was actually thinking about upgrading my low-efficiency Antec Truepower 330 (68% eff) for an 80 percent+ Fortron or Seasonic.

I figure my 225 watt would drop to 190 watts just with that change.

I'm also in the process of RMA'ing my original stepping Intel 3.2C (Sept 2003 pack date). The new one that should come back might shave quite a few watts off.

But all this is really moot for me this winter, residential electricity here in Calgary (through Enmax) just dropped from 5.966 cents per kwh to 5.934 cents/kwh < If there anything to be said about coal electrical production, its dirty but damn its cheap to generate.

Edit: oh, and a general rule of thumb, you want to never exceed about 70 percent of the capability of your powersupply, it will last longer and will *live* in the highest efficiency zone for that powersupply. Once you spike up into the 90 percent range your power efficiency goes in the toilet.

Same thing applies to network switches, you never want to hit 70 percent of capacity or you start to get packet collisions. At 90+ percent you are probably getting more collisions and dropped packet than packets that make it through the first time < Just like traffic jams.

[contoursvt]

I have a killawatt meter as well and I can say that I definitly need every last drop of my 550W antec PSU. I'm using about 230w at idle, about 320w while playing doom3. About 380w with sandra cpu test so I'm guessing if I ever have a situation where the CPU AND Video card are maxed, I'd hit over 400W without much trouble.

Then again I'm running a dual 3Ghz xeon box with 3 scsi drives but still... I think that previous link is being very VERY optimistic.

[Cafe_333]

I would say those numbers are accurate in a typical system - 1 cpu/hdd. Yours is pretty out there with dual xeons and three scsi harddrives. ;)

[cjpark]

I dare you to try running any modern computer on a 250 watt powersupply, It most likely will not turn on, or will quickly trip the overload circuit (or if you are unlucky, it can fry the computer)


Take a look at the system in my sig, my qbic came with a 250W psu. Never even a single instability problem caused by lack of power. Granted its not the highest power system with a huge overclock and 7800gtx but it is still quite decent and games very nicely. Not going to say I couldn't do with a 300W just for the extra headroom but this does work fine.

[deep]

Originally Posted by ZenOps
I dare you to try running any modern computer on a 250 watt powersupply, It most likely will not turn on, or will quickly trip the overload circuit (or if you are unlucky, it can fry the computer)

But I have an HTPC that runs comfortably off a 55W power supply. It was actually happy with a 40W PSU, but I got the 55 for free, so I decided I'd give myself a little headroom. 250W is quite a bit of juice....we should be designing more efficient PCs along with PSUs.

[Iblis]

maybe its bc i have a very up to date computer (video card needing power as well) but i had to get a 450 (and that was min recommended) watt power supply bc 300 - 350 was not enough and caused problems ...so i bought this one to be safe. this isnt normal?

[coriolis]

Go Pentium M go! :p

[matkun]

I run an Athlon 64 system with an x800 gto2, 3 HDDs and several fans. The CPU and videocard are overclocked a fair bit, and I can tell you that my APC Back-UPS ES 500 sometimes squeals about only having 2 minutes of battery run time left (in case of a power outtage) when I'm playing graphic intensive games. So I'd assume it's drawing a good 300W at those points.

It's amazing how much power a modern video card gobbles up.

Using an Antec SmartPower 2.0 450W PSU here with no instabilities.

[bmaz]

Let me just put my 2 cents in, not regarding that article but regarding Fortron.
I bought the Fortron AX400-PN from NCIX, only to discover a) despite its name its only a 350 watt PSU (400 peak) b) It doesn't work in 3 computers I have tested, and neither did its replacement from NCIX
Currently running a cheap $20 generic PSU from Factorydirect, sure its cheap and probably inefficient, but it works.

So to the point of this rant, beware of Fortron it's not as good as some people make it out to be.

[fakishan]

two budget computers are heating my friend's room. he turned the heaters off and put on the fan.

[goofball]

Let me just put my 2 cents in, not regarding that article but regarding Fortron.
I bought the Fortron AX400-PN from NCIX, only to discover a) despite its name its only a 350 watt PSU (400 peak) b) It doesn't work in 3 computers I have tested, and neither did its replacement from NCIX
Currently running a cheap $20 generic PSU from Factorydirect, sure its cheap and probably inefficient, but it works.

So to the point of this rant, beware of Fortron it's not as good as some people make it out to be.

spec's on the PC's?

that Fortron is a 12v based unit, and is not meant for 3.3/5v based systems.

[bmaz]

spec's on the PC's?

that Fortron is a 12v based unit, and is not meant for 3.3/5v based systems.
On the box for ther PSU it says straight up, Compatability with AMD K7 & K8.
It was tested in 2 AMD Athlon XP PCs (K7), and 1 P3 PC.
If you think its still good $40 and its yours.

[DirtyLude]

Unless I'm gravely mistaken, the wattage rating it output, not input. The efficiency of the PSU has no bearing on it's rating. A 300W PSU should put out 300W wether it's 65% efficient or 80% effecient. The only diffirence will be current draw from the wall, which has no bearing on the discussion.

[ShadowVlican]

Unless I'm gravely mistaken, the wattage rating it output, not input. The efficiency of the PSU has no bearing on it's rating. A 300W PSU should put out 300W wether it's 65% efficient or 80% effecient. The only diffirence will be current draw from the wall, which has no bearing on the discussion.
that's absolutely correct

the wattage rating is the output, but now a days you should look at effishsency as well when shopping for a new PSU, dont get a 500W PSU just because its there when you probably only gonna use 60W-100W most of the time
correct too, max efficiency occurs around 50-60% of the rated load (well something like that, just because it says 80% efficient doesn't mean it's 80% thru the whole power curve)

[Amourek]

This thread is seven months old.