is this FSP power supply any good ? FSP350-60THN-P (or too low on the 12v?)

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I know FSP is a good make, but judging by the spec, i'm not so sure
about this one.. .

I'm looking at the 300W PSU too, it's also quite low on the 12V.

all but one of my machines has a cheap graphics card. The one with the
non cheap graphics card, has
an nvidia geforce4 mx440 video card

I don't know if it'll suck too much out of a 300w,  if that low ampage
on 12v is existant and a problem.

I have an ammeter, i've measured volts, but don't know how to measure


Re: is this FSP power supply any good ? FSP350-60THN-P (or too low on the 12v?) wrote:

"  I don't know if it'll suck too much out of a 300w,  if that low
ampage on 12v is existant and a problem.  "

Without knowing what system you intend to put it in, no-one can really

Re: is this FSP power supply any good ? FSP350-60THN-P (or too low on the 12v?)

Cuzman wrote:
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i'm setting up a few systems. It should be possible to still advise
since these are fariyl typical.

An intel p4
An AMD  Athlon XP  1300+  and a 3000+

at most 2 CD drives and 2 HDDs.
sometimes 1 CD drive and 1 HDD.
sometimes 2 CD drives and 1 HDD

cheap video card that shouldn't suck much power.

I did hear that a quality 300w PSU with reasoanble ampage on the 12V
rail should be fine. even for 2 CD drives and 2 HDDs.   Or maybe I
should go for the 350w, though it still doesn't look like many amps on
that 12V rail.


Re: is this FSP power supply any good ? FSP350-60THN-P (or too low on the 12v?) wrote:

"  Or maybe I should go for the 350w, though it still doesn't look like
many amps on that 12V rail.  "

Are you aware that these are 24-pin PSUs with two 12V rails?  All Athlon
XP motherboards have a 20-pin connector.  You will need a 24-to-20-pin
adapter if you use these PSUs.

As for the 12V rails, 22A combined on the 300W and 25A combined on the
350W.  That's more than enough for those systems you quoted.  Having
said that, it's probably best to get 20-pin PSUs.

Re: is this FSP power supply any good ? FSP350-60THN-P (or too low on the 12v?)

Cuzman wrote:
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wow, thanks, you've saved me some potential problems.

My P4 MBRDs are ATX12V(so, 20+4). I haven't checked my MBRD manuals to
see if they will accept an ATX12V 2.0 PSU (24+4).
My (all?) AMD Athlon XP MBRDs are ATX.

I checked the pinouts, I don't think  the 24 pin rectangular plug has 2
extra 12V rails. It adds 4 to the 20pin plug to make the 24 pin plug.
yellow,red,orange,black. (so, 12V,5V,3.3V,0V)
So in total it has 2. (since the 20 pin only had 1 yellow, now the 24
pin has 2)

The separate 4 pin plug has 2 12V rails, but i've got that already on
my ATX 12V(20+4).

I will look for an ATX12V PSU for all my systems (I assume it'll work
in my ATX - AMD Athlon XP Boards).

I won't buy that PSU.

Thank you

note-  Paul points out in this post [1] that certain 20-24 pin adaptors
won't change the problem.  (it would fit without an adaptor - leaving 4
holes unplugged, but there are electronic issues).

[1] post- "24 pin ATX power vs 20 pin"

Re: is this FSP power supply any good ? FSP350-60THN-P (or too low on the 12v?) wrote:
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how about this one?


Re: is this FSP power supply any good ? FSP350-60THN-P (or too low on the 12v?)

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Where the 20 pin PSU meets the 20pin to 24pin adapter, still
has a six amp per pin limit, so fanning extra wires away from
the 20 pin PSU is not curing any problems. Where the adapter
meets the 20 pin power supply connector, it can get hot and melt
the plastic, if the six amp limit per pin is violated. In that
sense, a 20 pin to 24 pin adapter is delusional, since the
burning problem (if that is the problem you are trying to solve),
has now been moved to where the PSU meets the adapter.

While I like the simplicity of your "one size fits all" approach
to selecting power supplies, this is hardly a good way to do
things. If you are in a business, and are building systems for
a living, you should select several models, each suited for
a particular kind of build. If you were repairing a legacy
Athlon system, where the processor power comes from +5V, then
a power supply with a solid 5V @ 25A min would be the thing to use.
For a P4 system, as a bare minimum on a single output 12V supply,
I'd want 12V @ 15A , and this would leave precious little room if
a customer decided to add a kick ass video card at some future
date. With the wide variety of P4 systems, it is real easy
to exceed this minimum.

You don't state what speed your P4 system is. Some P4 processors
have a TDP of 130W, and with an assumed 90% Vcore conversion
efficiency, this is 144W input power, or 12V @ 12A. If the
supply only had 12V @ 15A, there isn't enough for the hard
drives and the like.

So, if you are going for a "universal" solution, you should
move up-market a bit. The price is doubled, but the "shoe
fits more feet".

+3.3V@32A, +5V@32A, +12V@26A, -5V@1A, -12V@1A, +5VSB@2.2A

That supply has enough +5V, for an older Athlon system.

It has enough +12V, for any reasonable combination of P4
and single video card. Sure, a 12A processor and a 10A video
card would be cutting it close (and that would be a high
end gaming system), as would a 12A processor and dozens of
disk drives. But for most simple desktop purposes,
with mid-range video cards, 26A should handle most of it.
And this supply is not really a good fit for SLI systems,
and you should custom select a supply for each SLI system
you build.

The main connector on that supply, is described as
"20+4-Pin". What that means, is the main power connector
is 24 pins, but 4 pins on the end unhook from the main
body of the connector. Thus, you have a 20 pin or a 24 pin
connector when you need it. Many supplies have a feature like
that. Note that you should not confuse the 4 pins that
detach, with the ATX 12V 2x2 power connector for the processor.
The ATX 12V 2x2 has two yellow and two black wires, and
supplies 12V to the processor. The detachable 4 pin block
on the main power connector has four different colored
wires, and should not be fitted to the processor power
connector by accident (someone managed to do that, but I
haven't checked the docs, to see if the pin patterns
of the nylon shells actually match).

To properly answer these kinds of questions, it is much
better to describe _exactly_ what hardware is in each
box. Why get half an answer, and only end up sending
the power supply back ?

And if you are in the business of building a decent number
of systems a year, buy yourself a clamp-on DC ammeter.
With one of those, you can clamp around all the red
wires on the main power connector, and measure the
total current in all those wires at the same time.
Repeat by clamping around the orange wires. The
ammeter adds the current of all the wires it
is clamped around. In a couple of minutes, you've
completely measured the amperes coming from the supply
(while, say, 3DMark or Prime95 are running). And then,
when you give the system to a customer, you know how
close to the limits the system is, and have a fair idea
later when the customer askes you "can I add an X1900XTX
to that box you built me ?".

This is the one I own. 380947 set to 40A DC. I've also
used this to service my central air conditioning (A.C.
current ranges), and the starter motor on my car (the
DC 400A range). Has a handy peak hold function. As far
as I know, this uses a Hall probe, to be able to handle
both AC and DC currents (by sensing the magnetic field). extech /380941_942_947.pdf


Re: is this FSP power supply any good ? FSP350-60THN-P (or too low on the 12v?)

Paul wrote:
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Thanks, I know I could avoid some of the thought by going for a good
make 400w one size fits most, PSU. But, sometimes I see an
exceptionally good deal on a good make of 300w PSU.   Also, I'm in the
uk , and we have less available models, higher prices and less good
deals. And i've found the FSP group PSUs (or one at least) with its
12cm fan to be not too noisy. And still cheap.

Is it the case that with the 24pin PSUs, the
places in the spec where it says "12VDC " are for the original 12V, the
12V1,  which goes to all the molex conectors and to the 2x2.  There is
only one 12V2 wire and it goes to the MBRD. (this must be the case,
also because an ATX 12V has no 12V2 and it has a 2x2)

My understanding of whati 've read is that with or without an adaptor,
if plugging a 24pin into a 20pin. (or vice versa?). The combined
current of 12V1 and 12V2 would go down 12V1, and if that exceeds 6A, it
could blow it and melt the plastic?
But  If I plug a 20pin PSU into a 24pin socket - or vice versa, it'd
leave 4 pins free. I don't see anything being combined.

Also, I don't see what the 12V2 powers. It only goes to the MBRD.  The
processor gets power from the ATX12V  (2* 12V1).     Any PCIe cards get
power from from the power supply molex connectors (with an adaptor), or
from the Power supply's PCIe connector, which woudl be 12VDC/12V1.

Regarding that device you mention,  I don't mind for some computers,
measuring the current with a multimeter and summing the currents - for
the sake of being able to do things - back to basics.  Though I might
get that device you mention.   I have some very small extension cables
like 3 inch or 6 inch, for the 4 pin molex , and the ATX12V 2x2.

I will insert those extension cables, cut them, put the multimeter in
series, and measure the current.    I've heard that a voltage drop at
the processor might not matter, because it's small and the voltage
regulators should take care of it.  And I guess that the voltage drop
on other devices may be insignificantly small and not matter.  Is that

thanks in advance

Re: is this FSP power supply any good ? FSP350-60THN-P (or too low on the 12v?)

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An ATX 2.0+ supply looks like this:

      12V2 ------------------ ATX12V 2x2 processor power

      12V1 -----+---+---+---- one pin of 20 pin section
                |   |   |
                |   |   +---- one pin of 4 pin clip-on section
                |   |
                |   +-------- disk drive connectors
                +------------ PCI Express connector (if present)

It is safe to have two separated 12V outputs, since the processor
power is fed immediately into a switching conversion circuit for
Vcore, and the two 12V sources don't mix on the motherboard. Also,
the 20(+4) pins feed the PCI Express slots some +12V, and the
video cards have their own switching converters on the graphics

A pre-ATX 2.0 supply would look like this:

            +---------------- ATX12V 2x2 processor power
   12V -----+---+---+---+---- one pin of 20 pin section
                |   |   |
                |   |   +----
                |   |
                |   +-------- disk drive connectors

With a PCI Express motherboard, if you have just one PCI Express
video card fitted, they use about 4 amps of the max 6 amps on the
one pin of a 20 pin section. So if you had a non-SLI config on
a motherboard with a 24 pin connector, the 20 pin section is
enough to power the video card slot, plus the current for the
fan headers.

The 24 pin connectors come in detachable (20+4) or non-detachable
forms. If you plug a 24 pin connector into a 20 pin connector,
four of the pins hang over one end of the connector. This is fine
as long as there are no components in the way. On one motherboard,
a capacitor gets in the way of those pins, and so a fixed 24 pin
connector type cannot be fitted.

The pins on the connector have current carrying limits. A single
pin on a 20 or 24 pin connector, can carry up to 6 amps. As more
current is carried, the wire and pin start to get warm. At some
point, that heat is too much for either the insulation on the
wire or the nylon connector shell, or the heat is too high for
the metal pin, and the metal finish deteriorates (oxidizes). The
6 amp number is established by the connector manufacturer, as a
safe value for the life of the product. (It melts at a
much higher current level.)

On a non-SLI motherboard, a 6600GT is measured at 4.35A from
the PCI Express video card slot. If you allocate 0.5A for the
fan headers on the motherboard, that means the motherboard is
using ~5A of current. If that motherboard had a 24 pin connector
(typical for a PCI Express motherboard), then plugging a 20 pin
connector that only has one wire for that 12V1 voltage, would be
sufficient to supply the ~5A.

On an SLI motherboard, two 6600GT cards would draw 8.7A total.
That would be too much to be safely carried with a single 12V
pin on the main connector, so a 24 pin power supply would be
recommended in that case.

Some motherboards also have a Molex connector on the motherboard,
and that is a mechanism to make room for more current to flow.

In the case of using an adapter:

   PSU ------- 20   20----------24   24pin_motherboard

Where the two 20 pin ends meet, there is only one pin to carry
the 12V current. Where the 24 pin meets the motherboard there
are two pins. In terms of the "hot spot", where the 20 pin
connectors meet is where the assembly will get hot. By using
the adapter, the point of restriction (only one pin to carry
the current) is where the 20 pin connectors meet. So the
adapter is not solving a problem, and is merely moving the
problem further to the left in the picture.

Some PSU and motherboard combos:

   PSU ------- 20   24pin_motherboard    (suitable for non-SLI)

   PSU ------- 24   24pin_motherboard    (SLI or non-SLI OK)

   PSU ------- 24   20pin_motherboard    (4 pins hang over)
                                         (single 12V wire was enough)

Some motherboards also have a disk drive connector which carries
current in parallel with the main connector. With that, you
get one pin on the 20 pin connector, and one pin on the
Molex disk drive connector, which is suitable for SLI usage.

   PSU ---+----- 20   24pin_motherboard   (SLI or non-SLI OK)
          +-- Molex   Molex_on_mobo

It is also perfectly OK to do this. In this case, there are two
pins on the main connector, and one on the disk drive connector.
The current is shared over the three pins, so the pins are lightly

   PSU ---+----- 24   24pin_motherboard   (SLI or non-SLI OK)
          +-- Molex   Molex_on_mobo


Re: is this FSP power supply any good ? FSP350-60THN-P (or too low on the 12v?)

Paul wrote:
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[this post may appear twice, google playing up]

Thanks, that has cleared up a lot of things,

So 24 into a 20(MBRD) is fine.   That was one of the PSUs I linked to
where a poster said I should be concerned.
The 24-20 adaptor is purely aesthetics, does nothing, and is
unnecessary. It doesn't have 2 wires into any pin. And regardless of
whether I use it, plugging a 24 psu into a 20 pin socket is fine,

And regarding 20pin PSU  to 24 with an adaptor, I see the problem,
you've explained that well.

But what of one other possibility.  20 to 24 without an adaptor, would
it start up? (since not all pins of the 24pin mbrd connector are
filled) ?

Furthermore, if a component e.g. a PCIe card with no molex, demands >6A
current fom the MBRD, would the MBRD try to draw it out of the one 12V1
pin, so, out of spec , and possible melting of the plastic ?

thanks in advance

Re: is this FSP power supply any good ? FSP350-60THN-P (or too low on the 12v?)

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Yes, as long as the power rating on the label is sufficient for
the job, everything is fine. Since a lot of 24 pin connectors
are detachable, the unneeded pins might even be unclippable.

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A couple of the power supply rails use multiple wires. This is
what it looks like when a 20 pin is plugged to a 24 pin mobo,
for the 3.3V wiring. 5V is a similar idea.

     PSU ---------+--------->   >-----+----- Mobo 3.3V ccts
    +3.3          |                   |
                  +--------->   >-----+
                  |                   |
                  +--------->   >-----+

In this case, up to 18A can flow through the 3.3V pins. If a
full connector had been plugged, then 24A can flow max. There
is no reason to think that even 18A are necessary. The load
will be less than that.

I believe the PCI Express slot connectors have 3.3V pins on
them, and the extra current carrying capacity of the 24 pin
mobo connector, is for PCI Express. But for video cards at
least, there is not currently a good reason to be using the
3.3V. You can run linear regulators from it, but that does
not seem to be the current practice. There are 3 "VCC3" pins
in this figure:

It is more likely that a PCI Express x1 add-in card would
use the 3.3V rails. But a typical card like that might use
1 amp or less of current internally.

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Sure, that is one possibility. But an article on Xbitlabs, where
they like to measure video cards, shows that when a video card
designer needs more than 4 amps or so, they draw the remaining
current from an AUX connector on the end of the card. So if
they needed 8 amps total on the card, they draw 4 amps from
the PCI Express slot connector and the other 4 amps from the
AUX. (Some video cards have two switching converters on the
card, so you can connect one converter to the slot, and the
other converter to AUX.)

The PCI Express slot connector has 5 pins for its 12V feed, and
each pin is rated at 1 amp. That is the reason they limit the
PCI Express slot consumption to slightly more than 4 amps. The
limit for the PCI Express slot connector is 5 amps. A 6600GT
slightly overclocked draws 4.35A for example.


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