Power supplies become increasingly expensive

Dom · Aug 31, 2003, 01:31 AM

CHOOSING A power supply is no longer as easy as it once was, specially when you're building a high-end Pentium 4 system.

The once easy question of "do you need an AT or ATX power supply?" has been replaced with "What kind of ATX?, ATX12V, SSI-compliant?, EPS12V one? with a 4-pin or 8-pin connector?" That must be my punishment for staying with a Pentium III as the fastest system in my data-room for so long.

My new 800 MHz FSB Pentium 4 motherboard recommends using an "ATX power supply designed for Pentium 4, with extra 12V connectors, that complies with Intel's SSI specification". I bought one supposedly P4-compatible 500W PS, and when I got home I realized it had 20 pins in the ATX connector, plus an extra square 4-pin 12v line. My mobo has 24 pins on the ATX plug. It didn't even fit. The amp rating was also a bit low on the -12v and -5v lines.

To confuse me even more, a quick Google search on "24 pin ATX" got me to a page that talks about the "EPS12V" standard, identified as "an extension of ATX for servers, with 24 pins instead of 20". My mobo manual does not mention "EPS12V" anywhere, perhaps this is the manufacturer's fault.

A quick search for "EPS12V power supply" didn't make things clearer, as I got a dozens power supplies listed, from $75 to $150 , most labelled for "dual Xeon servers", and some identified as "ATX12V + EPS12V dual". I even found one identified as "ATX + ATX12V + EPS12V SSI. 3-in-1". What a mess!

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Matth · Sep 1, 2003, 12:21 AM

Not long upgraded (though on a not particularly high end system)
Thunderbird 1200, 7200rpm HD, 384Mb SDRAM, DVD-ROM and CD-RW, Geforce 2 MX and PCI Modem, Ethernet, Sound & SCSI.

OLD PSU was 300w only 14A on the 3.3v, 12A in the 12v and 1.5A on the 5vSB
The new is a 400w dual fan, and the comparable figures are 22, 15 and 3

Not a huge improvement, but I can now get it to come back from sleep mode without crashing.

In current sytems, the CPU hits the 12v rail pretty hard, and this also powers drive and fan motors - a rather crass design in actual fact.

The PSU usually has a stonking 5v amperage, but apart from the drive logic on the 5v, not sure what else is split between the 5v and 3.3

Aug 31, 2003, 01:31 AM	#1
Dom DriverHeaven Extreme Member Join Date: Jun 2002 Posts: 12,940 Rep Power: 0	Power supplies become increasingly expensive CHOOSING A power supply is no longer as easy as it once was, specially when you're building a high-end Pentium 4 system. The once easy question of "do you need an AT or ATX power supply?" has been replaced with "What kind of ATX?, ATX12V, SSI-compliant?, EPS12V one? with a 4-pin or 8-pin connector?" That must be my punishment for staying with a Pentium III as the fastest system in my data-room for so long. My new 800 MHz FSB Pentium 4 motherboard recommends using an "ATX power supply designed for Pentium 4, with extra 12V connectors, that complies with Intel's SSI specification". I bought one supposedly P4-compatible 500W PS, and when I got home I realized it had 20 pins in the ATX connector, plus an extra square 4-pin 12v line. My mobo has 24 pins on the ATX plug. It didn't even fit. The amp rating was also a bit low on the -12v and -5v lines. To confuse me even more, a quick Google search on "24 pin ATX" got me to a page that talks about the "EPS12V" standard, identified as "an extension of ATX for servers, with 24 pins instead of 20". My mobo manual does not mention "EPS12V" anywhere, perhaps this is the manufacturer's fault. A quick search for "EPS12V power supply" didn't make things clearer, as I got a dozens power supplies listed, from $75 to $150 , most labelled for "dual Xeon servers", and some identified as "ATX12V + EPS12V dual". I even found one identified as "ATX + ATX12V + EPS12V SSI. 3-in-1". What a mess! Read More...

Sep 1, 2003, 12:21 AM	#2
Matth Flash Banner Hater Join Date: Jun 2002 Location: UK Posts: 3,411 Rep Power: 91 System Specs	Not long upgraded (though on a not particularly high end system) Thunderbird 1200, 7200rpm HD, 384Mb SDRAM, DVD-ROM and CD-RW, Geforce 2 MX and PCI Modem, Ethernet, Sound & SCSI. OLD PSU was 300w only 14A on the 3.3v, 12A in the 12v and 1.5A on the 5vSB The new is a 400w dual fan, and the comparable figures are 22, 15 and 3 Not a huge improvement, but I can now get it to come back from sleep mode without crashing. In current sytems, the CPU hits the 12v rail pretty hard, and this also powers drive and fan motors - a rather crass design in actual fact. The PSU usually has a stonking 5v amperage, but apart from the drive logic on the 5v, not sure what else is split between the 5v and 3.3