P8 connector is an old AT standard power connector for motherboards used along with P9 connector. Those two connectors would form a main connector or also known as P1 connector. Today those naming conventions have been slightly misclassified, where P8 is known as the 4x12V secondary connector with 8 pins by the mass. It is important to know that those are totally different connectors and shouldn't be mixed up.
When speaking about the 8 pin secondary connector it is important to remember that it is formed from 2 2x12v 4pin secondary connectors also known as the P4 (ATX12V) connector. Confusion of these names might have originated from this connector. I'd like to stress that it is important to keep in mind that it is NOT a P8 even if some places will call it so. In fact its name is EPS12V and was designed by SSI( Server System Infrastructures).
The reason i have spoken more about the confusion and the ESP12V more than the actual P8 connector is because when looking for P8 many look for ESP12V.
P8 and P9 power connectors
They are P8 and P9 They are P8 and P9
2 - Uses the P8 and P9 power connections.
You can identify a motherboard by the position of the CPU, along with the power connectors used. For instance, older baby ATX boards have the CPU positioned directly behind the PCI expansion slots. This can prevent proper seating of the expansion cards, and possibly over-heating to the CPU. The later full ATX (which is also the most common) now a days, but not the latest (BTX is the latest), has the CPU seated away from the expansion slots to provide more room and better ventilation within the computer case. Full ATX use a P1 power connector. P1 has a 20-pin connector that connects to a 24-pin P1 connector on a motherboard (ATX). While the older AT boards and Baby ATX both use P8 & P9 connectors. Sometimes these connections will be marked as "P1" or "P8" & "P9". The P8 connector provides 12volts of power, while the P9 provides 5volts. The later P1 connector added an additional 3.3volts to the already existing technology. This is a logical approach, as P8 & P9 are not combined, while the P1 was introduced combined.
Paramount Pictorial - P8-6 1939 is rated/received certificates of: USA:Approved
304 or 316 SS
Add the exponents to get p8
Paramount Pictorial - P8-6 1939 was released on: USA: 18 January 1939
P8 and P9
-12
Paramount Pictorial - P8-10 Diversity 1939 was released on: USA: 29 May 1939
Paramount Pictorial - P8-11 1939 is rated/received certificates of: USA:Approved USA:Passed (National Board of Review)