the powersupply myth?

[ZippyDan]

ive always believed in quality powersupplies. ive always believed u need enough wattage to run your stuff

ive heard the stories of shoddy power killing things
ive heard stories of not enough power killing things

i have 5 antec powersupplies... 2 400watt, 2 350watt, 1 300 watt. i am very happy with them

recently i bought 2 HP computers. these tiny cases come with miniATX powersupplies that output a whopping 180watts of power.

they came running Athlon XP 2600s. 256mb ram. Motherboard with onboard video and sound. 5400 RPM hard drives. CD-Rom.

i upgraded them to 512mb ram, 7200 RPM hard drive, and a PNY Geforce 4 Ti4200 128mb video card.

it handles it all without a hitch. 180 watts! I had more watts in my Pentium II!

i called HP and they said even their TOP OF THE LINE mediacenter computer with a Pentium4 3 ghz, DVD burner, Geforce4, 120GB HD, etc etc comes with the SAME 180 watt powersupply.

ive heard many times that a quality 300watt will beat a crappy 400 watt any day. so is this some super quality 180 watt HP is using? it looks like no-name crap to me that you often find in pre built computers.

how is this happening? is the Athlon XP 2600 a low power draw?
how much more can it take? any of you with a loaded HP computer?

i am disillusioned on high wattage quality powersupplies now! tell me something!

~Zippy!

 

[ScrapSilicon]

have you run MBM ..?

 

[TronX]

Normally you get what you pay for with PSU's.

 

[Lord Evermore]

OEMs get PSUs that are specially built, so even though it might be made by a company you've never heard of, they've built it to the specs of the OEM, who tests to make sure that it can power the exact system configurations they're using it in. A retail power supply is expected to be used in widely varying setups, so they can't make it a low wattage with tweaked outputs like Dell or HP gets.

There is however still a myth about high wattage being needed. The total wattage isn't really that important, it's how much power is output on the rails that are needed. Most PSUs have HUGE amperage coming out of the 5.5 and 3.3V lines, even though those are barely used even in a half-way loaded system. Then they have hardly enough power on the 12V line. Cheap 400W PSUs often have a 12V rating similar to a brand name 300W, and that's where the main difference is. It seems to be easy for a PSU maker to ratchet up the 5.5 and 3.3 rails, so they can make a high wattage PSU without putting the cost into making a good 12V rail (I assume that it costs more to do it right).

 

[zephyrprime]

they've built it to the specs of the OEM, who tests to make sure that it can power the exact system configurations they're using it in

Yeah but he swapped a lot of stuff out.

 

[zephyrprime]

7200rpm HD = 15 watts (max)
xp 2600 = 68watts (max)
1 512mb ddr dimm = ~9 watts (by the way, ddr heatspreaders are a joke) (max)
ti4200 = well, I don't know but it's gotta be less than 25 watts because that's the max supplied by a regular agp port.
fans = 3 watts
chipset = ? no idea. Seems like it'd be less than a ti4200 so let's say 15watts.

total = 135

Now there's some loss due to the power mosfets which might affect everything that gets power from the MB. What's the efficiency of a voltage regulator? Maybe 70-90%?

new total assuming 70% effiency for MB parts = 185 watts.

 

[astroview]

I have 3 HD's all 7200, a Voodoo 5 PCI card which requires a fair amt. of power, a P3 733 in place of a P2 400, and 2 CD drives on this dell powersupply and I get no problem at all.


part of me thinks its a myth too

 

[isaacmacdonald]

ehh... I've had problems with psu's before. I don't think it's a complete myth. My old 250 watt no name came with the case PSU would periodically stop seeing HD's on soft reboot and required a hard boot before they would reappear.

 

[Blastman]

Well, I would think you?re probably running very close to the limit on that psu. A 2600+ probably consumes about 60 ?65 watts, the motherboard (memory, onboard graphics, nic, etc) maybe another 20w, so you?re up to 85w, all on the 3.3+5v rails.

An Aopen micro-slim ATX case like this ...

http://www.aopen.com/products/housing/A340-series.htm

is P4 ready and only come with 180w or 200w psu?s.

The 200w model has a 120w combined 3.3+5v rating and the 180w model is 118w so running a M/B with integrated graphics, 1 HDD, no case fans shouldn?t present a problem.

Now, since you upped the graphics card to a 4200, (20w more?) and HDD to 7200 (3w more), you?re adding 23 watts to the 85 already being used = 107 watts , likely very close to what that psu is rated for. Now, assuming the psu can handle a little over it?s rating, which would be normal to expect (engineers put it in there with an Athlon), you?re fine.

If it?s a cheap psu and can only handle a little less than its rating. Smokin!

 

[human2k]

Some board's are just picky, i.e. Shuttle AK31A, K7S5A, etc.

 

[Wingznut]

It's all about quality... Not quantity.

You are no worse off with a quality 250w PS instead of a 400w PS.

I've been running my rig on a Lite-On 250w (pulled from an HP PC) for quite a while now.

 

[steell]

The largest psu that I have, is a PC Power & Cooling Turbo Cool 300, and I have used it on Athlon 1.4, dual XP1800's, dual 500/1meg Xeons, and several others

 

[onelin]

Part of it may be people overdoing things, but I think there's some truth. There are certainly some inconsistencies, though.

My Asus A7V333-R is one FUSSY board. The rig in it (in sig) has an Antec TruePower 430W. I had an Antec 300W and it was not enough to keep my USB mouse steady. I tried a noname 350W and it would not post with my fans spinning (scary thought). I've also had a noname PSU fry a brand new $300 GPU + more hardware, so I stick to brands from personal experiences...not word of mouth.

On the other hand, I am currently running a 200 or 250W micro-ATX and it's more than enough for a P4 2.53GHz w/ GF4, etc. Anything you can throw in this isn't going to change that...so in that sense it's kind of strange. I know this is the case for all microATX setups I've seen.

 

[jjyiz28]

there are exceptions to every rule. a shoddy PSU will result in an unstable computer system. if everything works good for you, then good for you. its like saying "i know first hand that my grandfather smoked 2 packs a day since jr. high school and he lived to be 100+ years old, and i know other people that smoked a long time and had no serious consequences, therefore im starting to not believe smoking is bad for you". catch my drift?

 

[ZippyDan]

ok i should rephrase. im not disillusioned on quality per se. but im not so sure that wattage really matters at all for the average user. i mean, none of my computers have more than what i have in those HPs (except maybe a PCI soundcard like Audigy in addition). so why do i have 400watt powersupplies? if a 180 can handle all that, a 300 should be able to handle a half dozen hard drives and more. i always got the impression from this place that i needed a 300 or even 350watt psupply AT LEAST for an Athlon system. but perhaps that is being safe rather than sorry

and on quality... these definitely arent HIGH quality powersupplies. they are probably just average. it leads me to conclude that you dont need high quality, you just need acceptable. you will only run into problems when you use BELOW acceptable quality powersupplies, or you use BELOW acceptable parts with BELOW high quality power.

that said, i like antec and will continue to buy more wattage than i need

really, i am amazed but also worried with these HPs. it seems too good to be true and i am waiting for it to fail any moment

in fact, one of the HPs has started not waking back up after it goes to sleep. my paranoia wonders if it is the powersupply or overheating (another problem with these pathetic HP cases), but its probably just software

Antec needs to make 300watt miniATX psupplies, I would buy them in a second

~Zippy!

 

[PowerEngineer]

I have to agree that most people probably aren't pushing their 400-500w power supplies anywhere close to their ratings. I also have my own no-frills PII system that cam with a 150w (I think...) power supply, and it's run well for years even after I added another hard drive and a CD burner.

I suspect the important issue on power supplies is how well they regulate the voltages they supply to your equipment. Investing a few dollars more in an oversized power supply should mean that your PC will be operating well inside the range where voltage regulation should be good. That said, it's probably more important to go with a high quality manufacturer (like Emerex?) than to just "super-size" a shoddy one.

 

[jjyiz28]

basically a low quality PSU will result in voltages that spike and dip very high and very low for very short time, and you cannot measure these with a multimeter since it goes by so fast. these dips and spikes will usually result in a system crash. a good PSU on the other hand will regulate the AC power comming from your outlet a lot better. the job of the PSU is to change it to DC power but also to "clean" out the power to some degree, good PSU do just that while poor ones do not clean them as well hence the spikes and dips. with that said you dont NEED a good PSU, just that it is good for your system, a good one will protect your motherboard a lot better.

if you have two high quality PSU, one is 200watts and the other is 400watts, then having a 400watt will be overkill for a system with not much stuff in it. the only difference will be one will supply more power than the other. if you have a good PSU 200 watt, and a POS PSU 400 watt, more than likely the 200 watt PSU will be able to supply more power than the other.

 

[bsr]

average computer only uses about 200watts of ac power I beleive (not including monitor, lcd's typically use pretty much no power at all tho). But yes It is very easy to push your 300 to its max with lights and lots of drives, so this is no myth. Thats why most people now go for 350 - 450 range.

 

[BenSkywalker]

Interesting that this topic should be up now. I just had a PC come through my 'repair shop'(a service I offer to friends and family, actually, it's still sitting next to my desk, just finished fixing it a few hours ago) and it happened to be a Hewlett Packard(Pavillion XT983 is written on the front) with an Athlon 1.4GHZ processor and 128MB of RAM, integrated graphics POS sound card etc. A stripper system with a decent CPU. This rig had a Bestec(?? I have the PSU right here, not familiar with them) '200 Watt Max'(150Watt using the rail ratings) PowerSupply in it and its problem was that it would boot in to Windows, stay up for about a minute or two and then shut down, not firing up again until the rig had sit for fifteen minutes or so. Checked that the description was accurate(repeatedly did the exact same thing), tossed in a 300Watt Enlight and voila, problem solved(not quite so simple, POS uATX PSU that was in the machine was half depth, had to modify the front panel and cut off the facing around the CDRW and slide the drive forward on the rails to squeeze it in there, PITA).

This machine is about a year old, came with no real frills and had nothing added to it(well, after I popped in the new PSU I added another 256MB of RAM, HP ships some of their XP machines with 128MB and uses 16MB for the integrated graphics, thing was significantly slower then a K6 300 I had here with 32MB EDO RAM running Win98) and it died in about a year. I've ran cheap @ss PSUs for years, then I had one go down and take a $150 mobo with it. Luckily this one was only the PSU itself that died, but I won't take the risk any longer.

The higher power rating on PSUs comes in handy when you have two HDs, two optical drives, a highly/overclocked Athlon or P4, a highly OCd high end vid card, lights inside your case and a dozen fans or so in your rig. You can usually 'get by' with a lower rated PSU, and sacrifice stability and longevity. Going with high end PSUs is worth it for a lot of us, they do provide real benefits.

 

[JeremiahTheGreat]

Well.... i ran a :

Duron 750

60GB 7200 Hardrive

512MB Sdram

Geforce2mx

all on a 80W IBM power supply... it was a good server, half the power drain was from the CPU itself, it was all good until one fateful day it was struck by lightening and the hardworking PSU was killed.

 

[Insidious]

I went with Enermax 465PE (430W) in my computers in the hopes that if it was overrated somewhat, maybe I would stress it less and it would live longer....

but these comps also ran fine on an enlite 300W.

I'm a hardware engineer and was more comfortable with a beefy quality supply, but I am not convinced it was absolutely "necessary"

-Sid

 

[XBoxLPU]

I have never owend a PS over 350W.

Currenlty running a PIV 1.6 system with an Enhance 300W and the system in my signature with an Antec 350W

 

[Tab]

Anyone heard of heavier powersupplies being a higher quality than light ones?

 

[glugglug]

Heh, check out the specs on their ultra-slim crap.

50W PSU on a 2.6GHz P4 system

Wonder what happens if you try to burn a CD with CPUBurn going in the background.

 

[Looney]

I don't think it's a myth... i've seen systems that won't boot with one 350watt cheap PS, yet if i stick in my Antec 300, it boots great. So yes, i would say HP's PS are very high quality.... it's not the total wattage that's important, but the quality that's coming out of the lines.