suitable power supply wattage


R

Ruel Smith

Matt said:
Hi all,
I'm just wondering if there's a way to work out a suitable power supply
wattage for a system. My 400w supply blew up over the weekend so I'm up
for a new one but wondering if I should get something bigger.

I'm running a Gigabyte GA-7VA mobo with an AMD Athlon XP 2000+ at the
moment although I'll probably upgrade the chip to a 3000+ towards the end
of the year. I've got a 52x24x52 CD-R/W drive, a 52x CD-ROM, floppy, a
20gig HDD (will be upgrading to around the 120gig mark soon). What else
uses power? I've got 6 powered USB ports, 3 of which have permanant
peripherals in them (printer/scanner with it's own power, modem & mouse),
but I often use up to 5 at once (with the camera and flash drive). The
only cards I've got at the moment are a 4x AGP card (64meg GeForce2) and a
LAN card. Oh and one 8cm case fan. I don't run the monitor through the
power supply, it get's it's own socket.

I've got an old 250w supply in there (with the 2 CD drives disconnected)
until I get the new one. So will 400w be enough to fulfill my upgrades (XP
3000+ cpu and 120gig HDD) or should I go 450 or 500?

Wattage is misleading. The important thing to look for is the amps put out
on the +12V line. Since most of the components you have that need power get
it from the +12V line that feeds the motherboard, that's where you need it
most. Many PSU's have high power ratings but don't supply as much juice on
the +12V line as a lower rated PSU.
 
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M

Matt Lobegeiger

Hi all,
I'm just wondering if there's a way to work out a suitable power supply
wattage for a system. My 400w supply blew up over the weekend so I'm up for
a new one but wondering if I should get something bigger.

I'm running a Gigabyte GA-7VA mobo with an AMD Athlon XP 2000+ at the moment
although I'll probably upgrade the chip to a 3000+ towards the end of the
year. I've got a 52x24x52 CD-R/W drive, a 52x CD-ROM, floppy, a 20gig HDD
(will be upgrading to around the 120gig mark soon). What else uses power?
I've got 6 powered USB ports, 3 of which have permanant peripherals in them
(printer/scanner with it's own power, modem & mouse), but I often use up to
5 at once (with the camera and flash drive). The only cards I've got at the
moment are a 4x AGP card (64meg GeForce2) and a LAN card. Oh and one 8cm
case fan. I don't run the monitor through the power supply, it get's it's
own socket.

I've got an old 250w supply in there (with the 2 CD drives disconnected)
until I get the new one. So will 400w be enough to fulfill my upgrades (XP
3000+ cpu and 120gig HDD) or should I go 450 or 500?

thanks

matt
 
S

SteveH

Matt Lobegeiger said:
Hi all,
I'm just wondering if there's a way to work out a suitable power supply
wattage for a system. My 400w supply blew up over the weekend so I'm up
for
a new one but wondering if I should get something bigger.

I'm running a Gigabyte GA-7VA mobo with an AMD Athlon XP 2000+ at the
moment
although I'll probably upgrade the chip to a 3000+ towards the end of the
year. I've got a 52x24x52 CD-R/W drive, a 52x CD-ROM, floppy, a 20gig HDD
(will be upgrading to around the 120gig mark soon). What else uses power?
I've got 6 powered USB ports, 3 of which have permanant peripherals in
them
(printer/scanner with it's own power, modem & mouse), but I often use up
to
5 at once (with the camera and flash drive). The only cards I've got at
the
moment are a 4x AGP card (64meg GeForce2) and a LAN card. Oh and one 8cm
case fan. I don't run the monitor through the power supply, it get's it's
own socket.

I've got an old 250w supply in there (with the 2 CD drives disconnected)
until I get the new one. So will 400w be enough to fulfill my upgrades (XP
3000+ cpu and 120gig HDD) or should I go 450 or 500?

thanks

matt
From what you say you whould be fine with a 350w unit.
Don't be fooled by big wattages, when it's bigger amperages and better
quality you actually need most of the time.
Look for something like an Enermax, Antec, Tagan or the like. With PSU's you
very much get what you pay for. Here in the UK I would expect to pay upwards
of £40 for something decent.

HTH
SteveH
 
D

dawg

Wattage isn't everything you need to know. Amperage is just as important.
Look for a PS with with 18+ amps on 12V and 30+ on 5V. Look at AMD's website
for some better ideas on approved PS's.
 
J

johns

I wouldn't upgrade that mobo. I don't think you can
get an Athlon 3000 in it to begin with. Equally, you
need to toss those 2 cdroms for a combo. The video
card is a dog. Time to upgrade the whole thing, period.

johns
 
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6

600watts

Hi all,
I'm just wondering if there's a way to work out a suitable power supply
wattage for a system. My 400w supply blew up over the weekend so I'm up for
a new one but wondering if I should get something bigger.

an antec 550watt supply is around $100.

What are you going to save buying something else ?

$80 ? 60 ? 50?

Your power supply makes it all happen.

bwwaahahahaha Buy what you want ;)
 
R

Ruel Smith

Where is everyone getting off that watts aren't important??


Voltage multiplied by the amperage equals wattage.

So you don't get amps with out watts and no watts without amps.

All power supplies that I've seen are sold by wattage output.

High and low voltage output/stability is most important with a wattage
capacity somewhat larger than the total installed equipment.

There are sites giving guidelines for watts consumbed by various
devises.

Overall wattage rating isn't important, as those numbers can be skewed, and
a cheap 400 watt power supply is often much less of a power supply than a
quality 300 watt power supply. It's most important, IMO, to check for the
amperage output on the +12V line, since that's where you need it most. Some
power supplies that boast 350 watts of power put out a pathetic 12 amps on
the +12V line. When your system has a powerful graphics card, and a
powerful processor like the current ones offered from Intel and AMD, you
need to feed it and all those other onboard components and anything else in
a PCI slot, and that's on the +12V line. There are other factors in
choosing a power supply, but this is the first thing I look at.
 
M

Matt

Matt said:
Hi all,
I'm just wondering if there's a way to work out a suitable power supply
wattage for a system. My 400w supply blew up over the weekend so I'm up for
a new one but wondering if I should get something bigger.

I'm running a Gigabyte GA-7VA mobo with an AMD Athlon XP 2000+ at the moment
although I'll probably upgrade the chip to a 3000+ towards the end of the
year. I've got a 52x24x52 CD-R/W drive, a 52x CD-ROM, floppy, a 20gig HDD
(will be upgrading to around the 120gig mark soon). What else uses power?
I've got 6 powered USB ports, 3 of which have permanant peripherals in them
(printer/scanner with it's own power, modem & mouse), but I often use up to
5 at once (with the camera and flash drive). The only cards I've got at the
moment are a 4x AGP card (64meg GeForce2) and a LAN card. Oh and one 8cm
case fan. I don't run the monitor through the power supply, it get's it's
own socket.

I've got an old 250w supply in there (with the 2 CD drives disconnected)
until I get the new one. So will 400w be enough to fulfill my upgrades (XP
3000+ cpu and 120gig HDD) or should I go 450 or 500?

thanks

matt

Here is an awesome deal on an Antec SLK1650B case + 350W supply combo
(apparently 45.64 + 9.10 S&H = $54.74 delivered)
http://www.ebuyer.com/customer/prod...9kdWN0X292ZXJ2aWV3&product_uid=145874&_LOC=US
http://www.pricegrabber.com/search_attrib.php?page_id=41&form_keyword=slk1650&rd=1
Looks like pricegrabber will pay you $5 to write a review, too.
See the reviews at newegg and elsewhere. See also the SLK2650 and
SLK3700 and Antec Sonata.

That 350W Antec would be more than adequate for your setup including
upgrade. Just don't buy a crummy supply. Antec and a few other brands
are very solid.

On the other hand, you could get a 430W Antec PSU only for $54 from
newegg after rebate. That would be a very nice big supply for the
future if you don't need a case:
http://www2.newegg.com/Product/Product.asp?Item=N82E16817103908
Oops, you also have to pay $7 shipping on that one.
 
J

jimkinman

Where is everyone getting off that watts aren't important??
From science class I think that I learned that:

Voltage multiplied by the amperage equals wattage.

So you don't get amps with out watts and no watts without amps.

All power supplies that I've seen are sold by wattage output.

High and low voltage output/stability is most important with a wattage
capacity somewhat larger than the total installed equipment.

There are sites giving guidelines for watts consumbed by various
devises.
 
M

Matt

Voltage multiplied by the amperage equals wattage.
So you don't get amps with out watts and no watts without amps.

True, at a given voltage, wattage and amperage are equivalent (but not
equal). Approximately what you said:

power(in watts) = voltage x current(in amps)

When you buy an ATX power supply, you are actually buying several
supplies (+12V, +5V, +3.3V, etc) contained in the same metal box. Each
component (hard drive, CPU, video card, etc) makes demands on some of
the several supplies. The point some people are trying to make is that
the wattages/amperages have to be adequate for each of those several
supplies---you can't just look at the total wattage.
 
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J

jimkinman

The average buyer has no idea what actual power they really need. Nor
do most really take the time to investigate each component, tally up
the various requirements by voltage tap, and then check to see if the
PS they will buy is adequate.

Too many simply think bigger is better. And, it certainly is not an
expensive mistake to buy 50-100 watts larger supply than you probably
need. What, maybe an extra $20 in a good supply.

So we tend to error on the safe side rather than risk under performance
or maybe even damage to components.

But, BUT, I still go back to my original thought above:

"High and low voltage output/stability is most important with a wattage
capacity somewhat larger than the total installed equipment."

Substitute "amperage" for "wattage" above if you like.
 
D

dawg

Where is everyone getting off that watts aren't important??


Voltage multiplied by the amperage equals wattage.

So you don't get amps with out watts and no watts without amps.

All power supplies that I've seen are sold by wattage output.

High and low voltage output/stability is most important with a wattage
capacity somewhat larger than the total installed equipment.

There are sites giving guidelines for watts consumbed by various
devises.

It's not that wattage isn't important. It's how it's distributed on the
various lines. Also,alot of cheap high wattage PS's aren't really as high
wattage as they sound. The specs can be very misleading.
 
R

Ruel Smith

Matt said:
Thanks for the replies guys. Info re amperage noted. One more question.
How does Thermaltake rate quality-wise when it comes to PSUs?

I'm not sure. They're a name that's got some credibility, and I doubt they
want to lose that credibility, so my guess it would at least be decent
enough.

Why not just get an Antec, like most people on here advocate? You'd save
yourself some headache.
 
M

Matt Lobegeiger

Thanks for the replies guys. Info re amperage noted. One more question. How
does Thermaltake rate quality-wise when it comes to PSUs?

ta

matt
 
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M

Matt Lobegeiger

Also, I'm checking out an Omni brand 500w supply on Ebay. According to the
specs on the unit it puts out 25A on the 12V, 50A on the 5V and 30A on the
3.3V. That seems pretty decent to me.

Anyone had any experience with Omni supplies before?

matt
 
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