Power Supply

Thanks

"TboXx" wrote in message
m...
I know this is a motherboard forum but im guessing you all would know if
your here anyway. Is there an easy way to tell what watt power supply i
should get? or any site you could direct me to,
Thanks

But what about that 800 watt supply that comes with that 10 dollar case.

"Darkfalz" wrote in message
...
"TboXx" wrote in message
m...
I know this is a motherboard forum but im guessing you all would know if
your here anyway. Is there an easy way to tell what watt power supply i
should get? or any site you could direct me to,
Thanks

Any good brand 300-400 watt should be fine. A good brand 250 watt will
perform better than a generic 400 watt, so obviously the most important
thing is to get a reputable brand (AOpen, Antec etc.).

Just like guitar or stereo receiver amplifiers... some of them are rated at
peak wattage, other
are rated RMS. Some of the cheap power supplies to make themselves look
good... probably
rate their supplies according to peak output...not sustainable without
overheating or becoming
overloaded and suppliing inferior voltage levels and noise. Good power
supplies will have
overload and short protection and noise reduction circuitry and so on... in
addition to what
the cheap supplies offer. I think a Zalman 300W is a good starting point...
and it is rated RMS.
COnnect your PC to a UPS too... a cheap 500 Watt UPS keeps your system
healthy too.

Jeff


"TboXx" wrote in message
m...
I know this is a motherboard forum but im guessing you all would know if
your here anyway. Is there an easy way to tell what watt power supply i
should get? or any site you could direct me to,
Thanks

Here is a link to a PSU calculator that might help.

http://www.jscustompcs.com/power_supply/







"TboXx" wrote in message
m...
I know this is a motherboard forum but im guessing you all would know if
your here anyway. Is there an easy way to tell what watt power supply i
should get? or any site you could direct me to,
Thanks

Paul,

An excellent and up-to-date summary.

Also see:-

http://www.firingsquad.com/guides/po...ly/default.asp
http://www.tomshardware.com/howto/20...pplies-01.html

John Lewis
================================================== ========
On Fri, 13 Feb 2004 17:00:33 -0500, (Paul) wrote:

In article , "TboXx"
wrote:

I know this is a motherboard forum but im guessing you all would know if
your here anyway. Is there an easy way to tell what watt power supply i
should get? or any site you could direct me to,
Thanks

A modern motherboard will have an ATX power connector and a 2x2 12V power
connector for the processor. So, you need an ATX power supply to power it.
At a minimum, those two connectors have to be connected to the motherboard,
to make it go. The 2x2 (i.e. four pin) connector is used exclusively by
the processor, and there is a conversion circuit on the motherboard, that
converts the +12V from the ATX power supply, into the 1.500V or so, that
a processor might need.

The ATX power supply has six outputs. The consumption from the -5V and
=12V outputs is so low, that there is no need to gauge the consumption.

The +5VSB output on the supply is used for "keep alive" power. That
power is used to save the contents of the DRAM chips, while the computer
sleeps. It powers the LAN chip, in case a wake up packet is sent to the
computer. It can be used to keep USB and PS/2 keyboards and mice powered,
so they can be used to wake a sleeping computer. If you download the
manual for the motherboard you plan on buying, there will be some
estimates in there as to how much power might be required. These aays,
many supplies have 1.5 or 2A for this function, and you can control some
of the load on this supply, by changing the USBPWRxx or PS2 PWR header
jumpers.

The +3.3V and +5V outputs on most supplies will be in the 20A or so
range. There is generally not enough information on power consumption
of the various parts of the computer, to say how much is enough. But
I can tell you by the process of deduction, that the consumption won't
be too high.

At one time, the processor derived its power, by converting the +5V output
to the lower voltage needed by the processor. With the increased power
consumption of processors, this function has been moved to +12V, and that
is why, if you try to reuse an old ATX power supply, chances are the
output on +12V will be insufficient for a new motherboard and processor.

To work out the numbers for +12V, seeing as it is critical, I use

Processor
P4 3.2Ghz/FSB800/512KB cache = = 8.4A@12V
Athlon 3200+/FSB400/512KB = = 6.4A@12V
including 80% conversion efficiency, the required current is
10.5A or 8A for a top end P4 or Athlon respectively.
Hard drive
2A during spinup of the disk, 0.5A while sitting in Windows desktop.
Allow 0.5A for a CD. If you don't have a lot of drives,
don't worry about spinup current, and concentrate on idle current.
Fans
Allow 1 amp for case and CPU fans.
Video card
Low end video cards use no +12V. An Nvidia FX5900 or an ATI9800
have a separate +12V cable, and as the video cards draw up to 70W
when gaming, a maximum of 6 amps would be required. Unless you
are buying one of these, a lesser number is more appropriate.
Total = 15A for a basic system, with some margin. If buying a
video card that requires extensive cooling, this number is more
like 20A.

Now, a reality check. The last computer I measured (2.6GHz/800 P4
865GE Northbridge) needed a total of 55W while idling in the Windows
desktop, and 120W while gaming (wall power). So, you can see that the
calculation above is quite pessimistic. That system didn't have a video
card, as it used the builtin graphics, so consumption could rise by
another 70W, if the system had a decent gaming video card in it.

Here are some sample products. The first table is for some
PCpowerandcooling.com products, considered the cadillac of power
supplies. For my purposes, the 350ATX meets the minimum +12V current
I would be after, so that is the smallest supply I would buy. You'll
notice that the bigger supplies mostly increase the capacity of the
rails you don't care about, so the 425ATX I would purchase to run
a FX5900 or ATI9800 has got a lot more +3.3V than I would ever need.

VOLTAGE --- +5V +12V +3.3V -5V -12V +5VSB

Turbocool 300ATX PFC 30A 12A 14A 0.3A 1A 2A +5 & +3.3150W
Turbocool 300 Dell 30A 12A 14A 0.3A 1A 2A +5 & +3.3150W
Turbocool 350ATX 32A 15A 28A 0.3A 0.8A 2A +5 & +3.3215W
Turbocool 425ATX 40A 20A 40A 0.3A 1A 2A +5 & +3.3300W
Turbocool 510ATX 40A 34A 30A 0.3A 2A 3A total510W

Here are the Antec Truepower series (antec-inc.com) - one step below
a cadillac.

VOLTAGE +5V +12V +3.3V -5V -12V +5VSB

TRUE330 30A 17A 28A 0.5A 1.0A 2.0A
TRUE380 35A 18A 28A 0.5A 1.0A 2.0A
TRUE430 36A 20A 28A 0.5A 1.0A 2.0A
TRUE480 38A 22A 30A 1.5A 1.0A 2.0A
TRUE550 40A 24A 32A 0.5A 1.0A 2.0A

Here, even the True330 is enough for a basic system, and the True430
is enough for a FX5900/ATI9800 gamer system.

Use a similar comparison with bargain supplies. Gauge them by output
currents and not total power.

HTH,
Paul

Feel the overall weight of the supply and compare that way, the heavier the better!
Wattage ratings are not as important as the quality of components.
One post stated that your board needs 90 watts and the drive needed 10.....
That may be the theoretical power draw but the real world start-up current is quite
different, somewhere on the order of 10~100x of what the label on the bottom of the
drive says that's where quality components will shine over any bogus rated cheapy
lightweight supply.

--
Mainboards, Videocards & CPU pin repair.

http://motherboardrepair.com


"TboXx" wrote in message
m...
I know this is a motherboard forum but im guessing you all would know if
your here anyway. Is there an easy way to tell what watt power supply i
should get? or any site you could direct me to,
Thanks

"Darkfalz" wrote in message
...
"TboXx" wrote in message
m...
I know this is a motherboard forum but im guessing you all would know if
your here anyway. Is there an easy way to tell what watt power supply i
should get? or any site you could direct me to,
Thanks

Any good brand 300-400 watt should be fine. A good brand 250 watt will
perform better than a generic 400 watt, so obviously the most important
thing is to get a reputable brand (AOpen, Antec etc.).

Bull****!!!

I just went from an enermax EG-431 (79$ 2-3 years ago) that was choking when
I ran 3dmark03 with an 2500xp being run as a 3200xp on an NF-7S to a 25$
600W power supply that runs 3dmark03 just fine at 11X200. Looped for 8
hours straight in test mode. The enermax wasn't a bad unit, its 15 amps on
the 12v line simply wasn't enough. 24 amps with the Lead Power did the
trick. having a 9800, 3 7200rpm HD, 2 dvd's and 4 80mm fans with some other
misc stuff didn't help.

http://tinyurl.com/2czrp

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Leadfoot wrote:
| "Darkfalz" wrote in message
|
|Any good brand 300-400 watt should be fine. A good brand 250 watt will
|perform better than a generic 400 watt, so obviously the most important
|thing is to get a reputable brand (AOpen, Antec etc.).
|
|
| Bull****!!!
|
| I just went from an enermax EG-431 (79$ 2-3 years ago) that was
choking when
| I ran 3dmark03 with an 2500xp being run as a 3200xp on an NF-7S to a 25$
| 600W power supply that runs 3dmark03 just fine at 11X200. Looped for 8
| hours straight in test mode. The enermax wasn't a bad unit, its 15
amps on
| the 12v line simply wasn't enough. 24 amps with the Lead Power did the
| trick. having a 9800, 3 7200rpm HD, 2 dvd's and 4 80mm fans with some
other
| misc stuff didn't help.
|
| http://tinyurl.com/2czrp


Hmm, 2-3 years ago with processors and video cards pulling what they do,
no wonder it was adequate (but its still crap compared to a brand name)

First off your EG-431, is probably a lesser quality variant of this one
(the EG451P-VE)

http://www.pcstats.com/articleview.c...eid=409&page=4

Older review (which is very favorable, but compared to todays PSU , and
the new ATX specification, its a DOG)

The important part is he

Operation Temperature

~ 0oC~25oCfor full rating of load,
~ decrease to zero Watts O/P at 70oC

Okay, that particular PSU does not use seperate voltage regulation on
each channel, so a heavy pull on your 12v rail will drag your others
down, and lower their true output you get that?

It will give that 15A on your 12v rail when its at 25 degrees Celsius.
Have you felt 25C ? its COOL, seeing as your body temp is like 37C, when
was (other than in the 15 seconds AFTER a POST) the last time you ever
had COOL air coming from your PSU? Every degree of heat it rises, it
LOSES efficiency, until it finally cant provide any of the rails proper
current, let along all of them.

Then go he

http://www.jscustompcs.com/power_supply/

Fire in your CPU/RAM/HD settings (I didnt know your RAM or extra
peripherals except the FANS, but I came up with 353W as your recommended
PSU.

That 4 year old powersupply, from the Celeron / Pentium 2 era, trying to
power a r9800 and a 2500xp (overclocked even! more draw on the rails)

No wonder you had problems.

The Enermax PSU has 0 problems, other than it was designed for far less
hungry devices and motherboards than todays computers, you putting a PSU
that couldnt realistically provide the current you needed, does not mean
that your POS 600w generic is better than an Enermax.

Philip
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I just went from an enermax EG-431 (79$ 2-3 years ago) that was choking
when
I ran 3dmark03 with an 2500xp being run as a 3200xp on an NF-7S to a 25$
600W power supply that runs 3dmark03 just fine at 11X200. Looped for 8
hours straight in test mode. The enermax wasn't a bad unit, its 15 amps
on
the 12v line simply wasn't enough. 24 amps with the Lead Power did the
trick. having a 9800, 3 7200rpm HD, 2 dvd's and 4 80mm fans with some
other
misc stuff didn't help.

I have 8 amps on the 12v line in my 250 Watt PSU and run 2 7200 RPM HDs,
CDRW/DVD, Geforce FX card, 3 internal fans and the biggest wattage hog of
all, a P4 3.0 GHz.

So what were you saying? Funny how my good brand 250 Watt with 8 amps on the
12v performs as well as your 600 Watt generic piece of ****.

I have that Enermax 431 PS that he is referring to, and I run my system just
fine with it. Have had no power related problems at all.

1 P4 2.8Ghz (OC'd to 3.1Ghz)
2 sticks of Mushkin 512 mb memory
4 7200 rpm hard drives (2 Raid-0 Arrays)
1 CD-R
1 CD-RW
1 Zip 250
1 dvd-+/-rw
Soundblaster Audigy Platinum
Network Card
GeForce FX
1 120mm fan
3 80mm fans

If this system runs fine off of the PS, then just about any around today
will.



"Darkfalz" wrote in message
...
I just went from an enermax EG-431 (79$ 2-3 years ago) that was choking
when
I ran 3dmark03 with an 2500xp being run as a 3200xp on an NF-7S to a 25$
600W power supply that runs 3dmark03 just fine at 11X200. Looped for 8
hours straight in test mode. The enermax wasn't a bad unit, its 15 amps
on
the 12v line simply wasn't enough. 24 amps with the Lead Power did the
trick. having a 9800, 3 7200rpm HD, 2 dvd's and 4 80mm fans with some
other
misc stuff didn't help.

I have 8 amps on the 12v line in my 250 Watt PSU and run 2 7200 RPM HDs,
CDRW/DVD, Geforce FX card, 3 internal fans and the biggest wattage hog of
all, a P4 3.0 GHz.

So what were you saying? Funny how my good brand 250 Watt with 8 amps on
the
12v performs as well as your 600 Watt generic piece of ****.