power supply help

B

buckyno2

I'm building a small form PC and need a good power supply. The mATX and
Flex PSUs I've seen all seem to supply about 180-250W but I need
350-400W (I think). Do they make small PSUs that powerful? I'll need it
to power a P4 2.2 CPU (400 FSB), two SATA RAID 0 drives, a DVD burner,
2 GB RAM and a GeForce 5200 graphics card plus the usual USB ports,
keyboard and mouse. Space is at a premium (I'm building it in a cigar
humidor). Will a 200-250W PSU suffice? What other specs should I look
for?
 
W

w_tom

Start by posting technical numbers from each component such
as the small form computer board. Don't do power requirements
at the 'total watts' level. Do power requirements for each
voltage.

The naive will instead recommend 500 watt power supplies in
desktop computers that even 300 watt supplies are sufficient.
Implied is that size or weight are also critical parameters.
So you must make decisions based on facts - not speculation.

BTW, that also means specs for the power supply. A power
supply without a one full page of technical specs is often
missing essential functions that were even standard 30 years
ago and necessary for your computer. Again, the answer begins
with technical specifications - including the all so critical
numbers. Power numbers should be defined for each voltage.
 
L

larry moe 'n curly

I'm building a small form PC and need a good power
supply. The mATX and Flex PSUs I've seen all seem
to supply about 180-250W but I need 350-400W (I
think). Do they make small PSUs that powerful? I'll
need it to power a P4 2.2 CPU (400 FSB), two SATA
RAID 0 drives, a DVD burner, 2 GB RAM and a GeForce
5200 graphics card plus the usual USB ports, keyboard
and mouse. Space is at a premium (I'm building it in
a cigar humidor). Will a 200-250W PSU suffice?
What other specs should I look for?

http://takaman.jp has a power estimator that seems to be more accurate
than most, but even its numbers are too high, except, strangely, its
+3.3V amp estimates, which seem to be 2-3x too low.

C'T magazine measured the actual power consumption of several XP 2400+
systems with NVidia ti500 graphics cards and found they averaged 150W
and maxed out at about 190W. I don't know how much power a ti500 uses
compared to a 5200, but I'm guessing more because it was a higher end
graphics card back then.

The biggest mATX PSUs I've heard of are 300W, but if your PSU is from a
major brand computer, it's probably really high quality. For example,
a Gateway's 90W PSU (Newton brand) was able to put out 120W for a
couple of days while in a box at 45 Celcius. If you really need more
power, how about running the disk drives off a second mATX? (hook its
green wire to the first PSU's green wire, and maybe connect a few 10W,
5-10 ohm resistors between the black ground and red +5V wires)
 
M

Michael Hawes

w_tom said:
Start by posting technical numbers from each component such
as the small form computer board. Don't do power requirements
at the 'total watts' level. Do power requirements for each
voltage.

The naive will instead recommend 500 watt power supplies in
desktop computers that even 300 watt supplies are sufficient.
Implied is that size or weight are also critical parameters.
So you must make decisions based on facts - not speculation.

BTW, that also means specs for the power supply. A power
supply without a one full page of technical specs is often
missing essential functions that were even standard 30 years
ago and necessary for your computer. Again, the answer begins
with technical specifications - including the all so critical
numbers. Power numbers should be defined for each voltage.

Depends on what P4? Willamette core very heavy on the juice (100W)
Northwood is best, but not available as new, and are expensive on Ebay. Spec
you have given is approx. 270W
Try http://www.jscustompcs.com/power_supply/
Mike.
 
M

manny

w_tom said:
Start by posting technical numbers from each component such
as the small form computer board. Don't do power requirements
at the 'total watts' level. Do power requirements for each
voltage.

And how is he supposed to do this accurately, at less cost than
a new power supply?
 

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