P4 Extension Cable

[comp1mp]

Hi,

I have seen Molex 4 Pin peripheral to P4 cable adapters.

The problem is, the pin out specs are different.

The molex 4 pin peripheral has a 12 vdc, 5 vdc and two ground pins.

The P4 has two 12 vdc and two ground pins.

Is it safe to use one of theses cable adapters? Do they fail under heavy load?

My instinct is that any motherboard that has a P4 input was designed for using two 12 vdc pins.

 

[Harvey]

I found a number of pics of this kind of adapter.

Note that the best of them show two yellow 12 volt leads from the standard Molex 4 pin adapter to the AT adapter. That is so the connector can safely provide enough current from the Molex to the AT connector so buy one that has two yellow wires.

Since the Molex has only one yellow wire, to avoid demanding too much current from it I would recommend using one that is on wires that go directly back to the PSU with no other devices connected to that particular wire run. For the same reason, use the Molex connector that is closest to the PSU to minimize the wire length.

 

[VirtualLarry]

it's really a question of how much current the P4 connector (and CPU) draws. The molex 12v line can carry 75W, I think, so any cpu up to that level should be fine.

 

[comp1mp]

Thanks both of you.

I notice in your picture Harvey that there are only 3 pins, so they don't even use the 5 vdc pinout, which makes sense.

I will be using an actual P4 extension, but seeing those made me curious.

In my opinion, making products like this available invite a lot of risk for less experienced users. A real P4 extension is not that much more expensive, and users with PSUs from earlier ATX specs without a P4 wire 'should' upgrade.

I had a gut feeling, but in my earlier years I would have bought this, plunked it on the end of long peripheral wire hooked up to a couple of peripherals and plugged it into my 125 watt CPU .