Trying to find out how many watts my power supply is.

I bought this computer retail, and I have no idea what power supply is in this thing. Is there some sort of program I can run that will tell me?

You have to open up the computer and look at the PSU itself. There is no other way.

Thurlow said:

I bought this computer retail

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Then your PSU is crap.

there "should" be a sticker on the PSU that will tell you the make and rudimentary specs

there is no software that would be able to determine its amp ratings
or total watts, software just monitors the current voltage as reported through the System Management Bus (SMB)
even if you where to employ a multimeter thats pretty much all youd be able to test

dandragonrage said:

Then your PSU is crap.

Click to expand...

Depends on the PC, really... Dell power supplies are excellent, Packard Bell are utter shit. If it's a local computer store's whitebox special, chances are the supply is shit.

Yeah, turns out it WAS a shit PSU. Any reccomendations for a 400W power supply? Preferably under $70.

Antec Truepower, Enermax, SilenX (not ahanix), Fortron/Sparkle.....Thermaltake, Zalman, Silverstone....

you can pick up a Sparkle 530w unit at newegg for$65. i believe the PCP&C Silencer units may be in your price range as well.

Antec TruePower

Also, there are some Aopen Refurbs on newegg, which are Fortron Source models, that are a great price ATM

Will it cause problems if I buy a 530W unit, but I only need like 380 watts? Will the extra wattage just not be used, or will it mess up anything?

no problems
power not needed is not produced
but watts is a poor indicator of a given PSU
there are many high quality 350 watt PSU that will kick ass on cheap 550 watt psus

-------------------------------------------- Cut & Paste from Corruption 101
Power Issues
There are three basic areas of power problems
1.Source Power Brown outs, blackouts, spikes\surges ect.
see > Power Conditioning and DIY UPS @ Dans Data, for the basics
In this category I would also place power issues due to pilot error, hard restarts and shorts, avoid both. Shutdown properly and pay attention when mounting your motherboard and routing power cables.

2. Under Power: Basically too many components for the power supply,
dont be decieved by wattage figures, its the amount of amps per rail that is really important.
See > Choosing the right Power Supply &
takaman's Power Supply Calculator rev0.61x
to determine the amps you need per rail

3. Voltage Stability Pretty much the all the following
[H]ardcore PSU info (Charts)
http://terasan.okiraku-pc.net/dengen/tester/index.html
http://terasan.okiraku-pc.net/dengen/tester2/index.html
(note the PC Power & Cooling, Antec, Ablecom, and Zippy)

In Japanese
But the graphs speak volumes
and the PSU are identified in English]

Continuous Power vs. Peak Power at Spin-Up
12V power profile (current vs. time) of an IDE/ATA hard disk at startup. You can see that the peak power draw is over quadruple
the steady-state operating requirement. The graph appears "noisy"
due to frequent oscillations in current requirements

Click to expand...

Peak vs. Continuous Power
Despite this extra capacity, it is still a good idea to not load up your system to the very limit of your power supply's stated power capacity. It is also wise, if possible to employ features that delay the startup of some disk drive motors when the PC is first turned on, so the +12 voltage is not overloaded by everything drawing maximum current at the same time.

Click to expand...

refering to the links above again
http://terasan.okiraku-pc.net/dengen/tester/index.html

note the consistent voltage instability at startup and shortly thereafter in those graphs

Winbond Launches New Bus Termination Regulator April 4th 2003

"Winbond Electronics Corporation, a leading supplier of semiconductor solutions, today launched the W83310S, a new DDR SDRAM bus termination regulator. The solution, new to Winbond's ACPI product family, is aimed at desktop PC and embedded system applications with DDR SDRAM requirements.

Computer systems architectures continue to evolve and are becoming more complex; CPU and memory speeds continue to increase ever more rapidly with every technology turn. More and more high current/low voltage power sources are required for PC systems. This is particularly true for high-speed components such as CPU, memory, and system chipsets. The performance of these components is highly dependent upon stable power. Therefore, motherboard designers require accurate, stable, low-ripple and robust power solutions for these components.

Many system designs use discrete components to implement bus termination functions. This approach creates several problems including poorer quality load regulation; higher voltage-ripple, increased usage of board space and inconsistent designs when different discrete components are used."

and just to reinterate this point one more time
http://www.anandtech.com/showdoc.html?i=1774&p=8
"the majority of damaged RAM returned to memory manufacturers is destoryed by fluctuations in the voltage."

the transient response is the critical measure, unfortunately its not a metric that is commonly supplied with the PSU specs
(this seems to be slowly changing, as some manufacturers are supplying the transient response now)

Transient Response: As shown in the diagram here, a switching power supply uses a closed feedback loop to allow measurements of the output of the supply to control the way the supply is operating. This is analogous to how a thermometer and thermostat work together to control the temperature of a house. As mentioned in the description of load regulation above, the output voltage of a signal varies as the load on it varies. In particular, when the load is drastically changed--either increased or decreased a great deal, suddenly--the voltage level may shift drastically. Such a sudden change is called a transient. If one of the voltages is under heavy load from several demanding components and suddenly all but one stops drawing current, the voltage to the remaining current may temporarily surge. This is called a voltage overshoot.

Transient response measures how quickly and effectively the power supply can adjust to these sudden changes. Here's an actual transient response specification that we can work together to decode: "+5V,+12V outputs return to within 5% in less than 1ms for 20% load change." What this means is the following: "for either the +5 V or +12 V outputs, if the output is at a certain level (call it V1) and the current load on that signal either increases or decreases by up to 20%, the voltage on that output will return to a value within 5% of V1 within 1 millisecond". Obviously, faster responses closer to the original voltage are best."
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Actually, as you know Ice czar power efficiency fluctuates with psu's when you go up and down in wattage usage, right?

Well I'd look for a review of a psu and estimate your wattage usage and find the most efficient at that level.. or really it's not that big of a change ~10%... well I guess that could be considered a high %age... considering the reason we use the type of power supply we are using now is because they are like 10-20% more effient than any other type.

I could be wrong?

~Adam

Effciency while an important metric, still doesnt rank in my book anywhere near voltage regulation \ transient response, I think its alot more easy to get rid of the extra heat generated by an inefficient PSU than it is to replace a stick of RAM that has fried

there are State of the Art +90% Efficient Switch Mode Power Supplies
they just havent reached us yet

the current situation is more an issue of a bungled spec and marketing pressures
on the one hand the FSB and its sensitivity to voltage has increased (because that is a spec that sells mobos)
and the onboard voltage regulation components to address it vary from mobo to mobo
(see above Winbond Press Release) some good other less so

and then there is the increasing amount of power required
to the point where the latest ATX spec calls for more 12V connectors
(and actually dictates, a new PSU Power connector with 24pins)
but the mobo manufacturers havent implemented it, because they dont think doing so will make their customers happy and so there is a confusion of solutions, meanwhile in the server market the spec has definatively changed to EPS12V

cut and paste

ATX = 20 pin plug, your Pentium III's ATX connector and PS

ATX12V v1.1 = 20 pin atx connector + 4-pin plug for "Additional 12V" (same pdf as above)

ATX12V v2.0 = 24 pin atx connector + 4-pin plug for "Additional 12V"

EPS12V = Power supply with 24-pin EPS12V connector, plus one 8-pin "additional 12v connector".

SSI = Intel spec, which, among other things, defines the "EPS" "enhanced" ATX specification

FormFactors.org


Power supplies become increasingly expensive June 13, 2004

He explained that the later P4 CPUs take their power from a 12 Volt feed and, using the onboard voltage regulators, generate the high current, low-voltages they need to operate (anywhere from ~ 1.6V to around 2.7V). So the first requirement is a PSU that has plenty of power available from the 12V supply. Since the older ATX compatible PSUs didn't supply much current from the 12V section you have to ensure that your new PS delivers enough current (or power in Watts) from the 12V section. That's why using your old P3 ATX PS is a big "no-no".

He then described the history of the post-P3 power supply mess:

The earlier Athlon motherboard manufacturers decided to solve the 12v problem by using an additional 4-pin square connector to get the extra 12V those CPUs required. However many older PSUs didn't provide the 12V 4-pin square connector.

The motherboard makers then wised up and decided that there was nothing magical about a square 4-pin connector, so they put a normal hard disk type socket on the motherboard and provided the 12v power via a standard hard disk (4-pin inline) connector. Problem solved - you may now use your older PSUs provided they supply sufficient 12V current (many did not).

Further confusion came from PSU manufacturers not specifying the capabilities of the PSU in a way that allowed the end user to verify it's 12V power output rating.

In the meantime the ATX spec was saying "use the new 6-pin" inline connector - and very few motherboard makers implemented it.

Just to be sure, some motherboard makers, implemented *both* the hard disk style 4-pin inline connector and the square 4-pin connector. They said "use either or both in any combination you like".

The spec then evolved to the 24-pin main connector. Again, most motherboard manufacturers did not wish to make their customers mad by mandating that they replace their power supplies. This might cause their customers to avoid motherboard upgrades. Some used a "special" 24-pin connector with the extra 4-pin connection blocked off, or colored so that the user could plugin a 20-pin plug into the correct end of the 24-pin socket on the motherboard. Many others simply ignored the 24-pin requirement in the specs. Again - problem solved - use your older PSU.

Click to expand...

so one one hand you have alot of solutions that are under powered, and that in turn means that voltage regulation in the newer boards suffers
and that inturn means that on boards with less than ideal onboard voltage regulation
RAM Fries

and all because "some" manufacturers dont want you to buy a new PSU inorder to buy thier board, and use cheap components

it reminds me of the capacitor balls up of a few years ago
so they could save pennies per board

offhand I say now is a good time to stick with trusted mobo and PSU manufacturers
and perfreably those that adopt the new ATX12V 2.2 standard or EPS12V
and that we need to bite the bullet and upgrade to those supplies

but everyone is nervous with all the new standards changes
will it fit in my BTX? will it work with PCI Express is it enough?
all of a sudden its appearant that a PSU is no longer an infrastructure investment
where it was in the past, and just as thats happening, the price goes up
well... thats the cost of running CPUs, video Cards and RAM 2, 3, and 4, 10 times as fast as the last time you bought an ATX or changed PSU standards


sorry for the rant
sort of a dry run for a FAQ Im planning