What PSU rating for Athlon 2400 with 6 HDDs?

[kony]

Yes you do. The lowest rated supply I use for Athalon systems is 400
watts, and that is only with one HD.
Anymore and I go with a 500 watt.
Believe me if you really try and do any serious computing loads with
an under rated power supply you're asking for serious migraines.

It's true that an insufficient power supply can cause both
instability and eventual damage, but the typical Athlon
system does not need 400W, and there is almost no "PC"
system that needs 500W, even if the vast majority of the
current were concentrated on only the 5V or 12V rail.

With a typical PC, that being current-gen CPU, a couple hard
drives, budget/low-end video card, etc, 300W PSU in a good
name brand is sufficient. SFF systems demonstrate every day
that even a 180-250W PSU will run a modern built with enough
margin for another hard drive or two... but the PSU may need
replaced sooner.

Generics on the other hand, are a lottery. Their wattage
rating means almost nothing, they can only be assumed to be
somewhere inbetween 200W and 400W without further evidence.

 

[kony]

Correct. And that is the lowest one should use.
I do video/film editing on Athalons and anything lower than 400 will
give you constant locks and blue screens.
The inrush and overcurrent ratings are critical too.
At least 30 on the 5v and 25 on the 12v is required.
You can NEVER have to much power.
A good trick is to split the load between multiple psu, does require a
bit of moding though.

Not true. I also have done quite a bit of video editing and
other full loads for extended periods of time and am quite
sure that 30A on 5V is not needed if CPU doesn't use 5V for
VRM circuit, and that even if CPU uses 12V for VRM circuit,
it will not need 25A. If you had instability you either
have very atypically high load beyond what was mentioned, or
very poor power supplies.... like generics that are quite
overrated.

 

[Chip]

Nexus is made by Fortron-Source, one of the best PSU makers in the
world, but I don't know if the 16A @ +12V is enough for all that
hardware. One person found that his XP1800+ system with five HDs
(RPM unknown) and a couple of CD drives consumed only 160W from the AC
lines, meaning that the computer was taking about 120W. And in 2002
C'T magazine measured several computers equipped with XP2400+ CPUs,
256M DDR, and GeForce3/Ti500 graphics cards and found that it took
about 9A @ +12V, 2-4A @ +5V, and 9-12A @ +3.3V.

The problems tend to be under peak load, especially at cold boot. At cold
boot, when all the disks are spinning up for the first time, likewise the
fans, likewise the CPU initialising, the peak current required can be much
higher. And then you find problems like perhaps your soundcard doesn't
always initialise properly (which used to happen to me with an old Enermax
350w PSU).

Chip

 

[Watson A.Name - \Watt Sun, the Dark Remover\]

With 6 drives I'd go with a larger power supply, get at least a 450W
supply or even larger. An Antec 550W supply is only $108. You don't want
to waste your time hunting down system glitches because you saved 30 bucks
on a power supply.

The wattage is important, but int his case, the +12V is more important
because of the very high +12V current needed to start up the hard disks.
Someone else mentioned 2A per HDD at atartup but there are also other
+12V loads, such as the fans. So getting a PSU that has a lot higher
than usual +12V current rating is a _must_.

One other important thing. Putting 6 hard disks in a case demands that
there be a lot of air circulating around them. If you don't keep thenm
cool, then the ones closest to the middle of the stack will overheat and
die. I've seen that happen in servers. You might consider using
external HDDs if you have problems.

 

[Watson A.Name - \Watt Sun, the Dark Remover\]

You really can't have too much, but you can have too little.

What kind of twisted logic made you come up with that statement?
Why don't you say what you _really_ mean?
"You really should buy a PSU that has too much, rather than too little
power."

When it comes to power supplies, I would just get a good name - like Antec
True Power, around 430 watt to be safe.

 

[Watson A.Name - \Watt Sun, the Dark Remover\]

Heh..
I dunno
Climb a highline pole and put a 5v light across the 15kv lines ;P

Brilliant!!

 

[David Maynard]

Brilliant!!

Briefly

 

[General Schvantzkoph]

It's true that an insufficient power supply can cause both
instability and eventual damage, but the typical Athlon
system does not need 400W, and there is almost no "PC"
system that needs 500W, even if the vast majority of the
current were concentrated on only the 5V or 12V rail.

With a typical PC, that being current-gen CPU, a couple hard
drives, budget/low-end video card, etc, 300W PSU in a good
name brand is sufficient. SFF systems demonstrate every day
that even a 180-250W PSU will run a modern built with enough
margin for another hard drive or two... but the PSU may need
replaced sooner.

Generics on the other hand, are a lottery. Their wattage
rating means almost nothing, they can only be assumed to be
somewhere inbetween 200W and 400W without further evidence.

The OP seems to be talking about a file server not a desktop PC. It's
hard to imagine why you would need 6 drives on a desktop. The disks are
going to be working much harder in a file server then they would be in a
PC. The symptom of a power supply problem on a file server is that a disk
suddenly drops off line, they system continues to run but you've lost that
drive until you do a reboot. It's very annoying. It's much better to spend
a few more dollars to get a robust supply. There will be $1000 worth of
drives in that system, it's silly to worry about 30 or 40 bucks extra for
a 550W supply vs a 350W.

 

[General Schvantzkoph]

One other important thing. Putting 6 hard disks in a case demands that
there be a lot of air circulating around them. If you don't keep thenm
cool, then the ones closest to the middle of the stack will overheat and
die. I've seen that happen in servers. You might consider using
external HDDs if you have problems.

You solve the problem by getting a server case that's designed to handle a
large number of drives. You want a case that has good air flow over all of
the drives. It's OK to passively cool a single drive in a desktop machine
because desktop drives have very little activity. In a fileserver the
drives work much harder so you need to blow air over them to keep them
cool.

 

[kony]

The OP seems to be talking about a file server not a desktop PC. It's
hard to imagine why you would need 6 drives on a desktop. The disks are
going to be working much harder in a file server then they would be in a
PC. The symptom of a power supply problem on a file server is that a disk
suddenly drops off line, they system continues to run but you've lost that
drive until you do a reboot. It's very annoying. It's much better to spend
a few more dollars to get a robust supply. There will be $1000 worth of
drives in that system, it's silly to worry about 30 or 40 bucks extra for
a 550W supply vs a 350W.

Possibly a file server but then why the Athlon XP2400?
Seems a bit overpowered if the goal is to minimize power
usage, or rather, buy an economical PSU for the role played.

Even so you may be right, _IF_ the drives, data, or
function, productivity loss is significant from a failure
then it's easily justifiable to budget more for larger
wattage PSU.

 

[VWWall]

That way, he would have about 250-300 watts left over on each!

That way he could avoid about a half hour's mental work.

Except he would have to figure how to rig a computer using four power
supplies instead of one.

Or he could put a 12V automobile storage battery and charger under the
desk and hook all the drive's 12V input to that! ;-) That way if he had
a power failure, the drives would keep spinning and upon power return,
he wouldn't have to let them warm up as another poster suggested. :-(

Seriously, once the drives are spun up, they require only ~1 A each.
Fans have even less requirements: < 1/2 A each.

Some motherboards and video cards use considerable 12V power, but this
is not the case here.

Having more real real available than is required does nothing for
stability or anything else!

Virg Wall

 

[Tom MacIntyre]

With that many Hd's I'd be thinking about dedicating one good psu to
the motherboard and the optical drives/floppy and using separate
supplies for alll those Hd's.(maybe 2 drives to a psu rated at at
least 350-400 watts.)
Depends on what type of computing you'll doing and how intensive too.

I forget, but do the drives use both +5 and +12, and, if so, will this
arrangement be enough to regulate a supply?

Tom

 

[Chip]

I forget, but do the drives use both +5 and +12,
Yes.

and, if so, will this
arrangement be enough to regulate a supply?

I don't know what you mean by that.

Chip

 

[Franklin]

The OP seems to be talking about a file server not a desktop PC.
It's hard to imagine why you would need 6 drives on a desktop.

I am the OP. I guess I am a bit weird but it is my home PC on my
desktop and used as a single user system. I have 6 drives to back up
partitions and to store my data.

The disks are going to be working much harder in a file server
then they would be in a PC. The symptom of a power supply
problem on a file server is that a disk suddenly drops off line,
they system continues to run but you've lost that drive until
you do a reboot. It's very annoying. It's much better to spend
a few more dollars to get a robust supply. There will be $1000
worth of drives in that system, it's silly to worry about 30 or
40 bucks extra for a 550W supply vs a 350W.

Nowadays these sort of drives cost about $100 each (for 120 GB or
thereabouts). The older drives cost me more but are even cheaper to
replace at today's cost.

 

[Franklin]

You solve the problem by getting a server case that's designed
to handle a large number of drives. You want a case that has
good air flow over all of the drives. It's OK to passively cool
a single drive in a desktop machine because desktop drives have
very little activity. In a fileserver the drives work much
harder so you need to blow air over them to keep them cool.

I am the OP.

I have solved my problem of heat generation by not buying IBM/Hitchi
or Western Digital hard drives. Those drives undoubedly perform well
but they get way too hot and can be a bit too noisy for me.

My hottest drive is a Seagate Barracuda and Dtemp from
http://private.peterlink.ru/tochinov/ says it runs at 41 C. It is
the system drive with most of the read/write action, The other
drives run at a comfortable 30 to 35 C when idling.

My cooling is very simple. I have the PSU fan, the cpu fan and one
80mm case fan which I run at less than half speed to keep the noise
down. The ambient room temp is about 20C.

It is almost a 'bumble-bee' system. I am told that early dynamics
theory calculated that the bumble-bee should not be able to fly.
Theory suggests my PC should not be so cool nor so quiet. But in
real life it works.

 

[Tom MacIntyre]

I don't know what you mean by that.

Chip

Computer supplies need to be regulated to achieve the correct output
voltage, and both the 12 and 5 volt supplies may need to be loaded to
a certain level to achieve this.

Tom

 

[Duddits]

What rating PSU should I use on a system which has an Athlon 2400+
with a modest graphics card (old GeForce2 MX 32MB) and 768 MB of SD-
RAM. Unusually, it will have *SIX* IDE internal hard drives.

All the rest of the system is pretty normal with no overclocking on
the cpu.

Would a decent 350W PSU be enough? I am thinking of this Nexus PSU.
http://www.nexustek.nl/nx3500.htm The specification chart shows
current delivery at min load, normal load, max load:

+3.3V 0.3A 14.0A 21.2/28A
+5V 1.0A 12.7A 30/25.5A
+12V 0.2A 4.5A 16A

(1) +3.3V & +5V total output not exceed 220Watt.
(1a) When +3.3V is loaded to 28A, then the +5V maximum load is 25.5A.
(1b) When +3.3V is loaded to 21.2A, the +5V maximum load is 30A.
(2) +3.3V & +5V & +12V total output not exceed 330Watt.

Thermaltake 420 watt PurePower $39.00
An excellent power supply that will meet your needs.
http://www.newegg.com/app/ViewProductDesc.asp?description=17-153-006&depa=0

regards

Dud

 

[kony]

Computer supplies need to be regulated to achieve the correct output
voltage, and both the 12 and 5 volt supplies may need to be loaded to
a certain level to achieve this.

Tom

Yes a drive, two at most is plenty of load for regulation
within tolerances on any halfway decent power supply.

 

[Glenn Gundlach]

You don't want to waste $30 for nothing, either.

Actually I would. It takes very little time use up $30 tracking down
the problem. And THEN, you STILL have to get the bigger supply. After
the computer and 6 HDDs, $30 is nothing.
My $0.02
gg

 

[Michael Brown]

(irrelevant newsgroups removed)

With that many Hd's I'd be thinking about dedicating one good psu to
the motherboard and the optical drives/floppy and using separate
supplies for alll those Hd's.(maybe 2 drives to a psu rated at at
least 350-400 watts.)

Umm, wha? That's complete overkill. A high-end drive ideally likes to eat
about 40W spinning up IIRC (mostly on the 12V line), so you'd have about 3A
per drive peak on the 12V line. For any halfway reasonable, or even
completely useless, PSUs you should be able to fit 3 drives/PSU, and
probably 4 or 5 if it's a reasonable one. 20A on the 12V line (with the rest
of the lines essentially unloaded) should be sufficient to power up all 6
drives. Also, if the drives are designed to delay spin-up when they're the
secondary drive, you should be able to handle double the number of drives
per PSU (ie: 6 drives if you've got ~10A available on the 12V line).

Incidentally, does anyone know how many "normal" SATA controllers implement
sequential spin-up?

Depends on what type of computing you'll doing and how intensive too.

This is irrelevant to how many you can run off a single PSU. Power usage for
even high-end drives is below 10W mark (usally <400mA on 12V, <1A on 5V)
while operating, so you could have all six drives running off a PSU that's
only capable of 3A on the 12V line (though of course they won't have a hope
of spinning up ...).