Power Supply Required for P4 ??

Have some old P2 computers was going to upgrade. Believe they have 250Watt
Power Supplies. Will that same case and power supply work with the newer
Pentium 4 Motherboards and CPU's or will it be insufficient?

as a general rule, P4 MB's require a power supply that has a 4-pin (not the
usual molex drive connector, this one is square) +12volt connector for the
motherboard in addition to the standard 20-pin MB PS connector.

If your 250watt supply has the extra 4-pin +12v connector it may work
although 250watts is the minimum I would use for a P4 system these days.

"Al Franz" wrote in message
newsjAqb.132336$Tr4.338489@attbi_s03...
Have some old P2 computers was going to upgrade. Believe they have
250Watt
Power Supplies. Will that same case and power supply work with the newer
Pentium 4 Motherboards and CPU's or will it be insufficient?

P4's require a special PSU that has an extra connector for the CPU.

--
DaveW



"Al Franz" wrote in message
newsjAqb.132336$Tr4.338489@attbi_s03...
Have some old P2 computers was going to upgrade. Believe they have
250Watt
Power Supplies. Will that same case and power supply work with the newer
Pentium 4 Motherboards and CPU's or will it be insufficient?

"Al Franz" wrote in message news:ojAqb.132336$Tr4.338489@attbi_s03...

Have some old P2 computers was going to upgrade. Believe they
have 250 Watt Power Supplies. Will that same case and power
supply work with the newer Pentium 4 Motherboards and CPU's or
will it be insufficient?

I was able to run a 1.7 GHz P4 Celeron with CD and HD drives and a
low-power video card from a cheapo 250W (so bad that PC Power &
Cooling used it as an example of what a bad PSU was like), but a 1.3
GHz Duron mobo with nothing but the same video card cause the PSU to
shut down in 30 seconds. But PSUs vary a lot in quality, so your
250Ws may have no trouble at all even with much higher power
consumption.

Most P4 mobos have a separate square 4-pin connector for the +12V
because they power the CPU from the +12V rail, and with these you need
a similarly equipped power supply or else the lone +12V wire on the
20-pin ATX connector could overheat. But some Asus mobos use a disk
drive power connector instead, and there are adapters to convert this
type of connector to the square 4-pin type.
But not all P4 mobos run the CPU from the +12V rail, and I run my 1.7
GHz P4 Celeron from an ECS P4S5A2 that has only the 20-pin ATX
connector.

There's a power needs estimator at http://takaman.jp/ that seems to
give accurate results, but for P4s it always assumes that the CPU runs
from the +12V instead of the +5V.

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Jim Taylor wrote in message


Most P4 mobos have a separate square 4-pin connector for the +12V
because they power the CPU from the +12V rail, and with these you need
a similarly equipped power supply or else the lone +12V wire on the
20-pin ATX connector could overheat. But some Asus mobos use a disk
drive power connector instead, and there are adapters to convert this
type of connector to the square 4-pin type.

Using an adapter isn't a good idea.

http://www.intel.com/support/motherb...top/12v2x2.htm

Thanks for the link and the warning.

I can see how an adapter could cause problems with a really power-hungry
CPU, but Germany's C'T magazine measured XP2400+ CPUs as drawing less 10A
@ +12V, which to me (I'm no expert) means that two wires (mobo + disk drive
cables) should be able to carry the current (when I checked +5V wires with
a clamp-on probe they shared current equally). But I have to admit that
I've never used one of those adapters because I'm too cheap and have
instead soldered square 4-pin connectors from junked PSUs to the circuit
boards of good PSUs.



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Jim Taylor wrote:

Most P4 mobos have a separate square 4-pin connector for the +12V
because they power the CPU from the +12V rail, and with these you need
a similarly equipped power supply or else the lone +12V wire on the
20-pin ATX connector could overheat. But some Asus mobos use a disk
drive power connector instead, and there are adapters to convert this
type of connector to the square 4-pin type.

Using an adapter isn't a good idea.

http://www.intel.com/support/motherb...top/12v2x2.htm

While I agree that using an adapter isn't the greatest of ideas, I
disagree with Intel's contention that most standard ATX PSUs provide
only 5 amps on the +12v output. That's only 60w. That's bull. I think
10 amps on the +12v is closer to the truth except on extremely low
power (150 watts) PSUs.

I am more troubled by attempting to shove too much current through one
wire, and an EXTRA male/female contact combination.




--
Better than hearing "Lady Day", or checking in at Monterey...