Hardware Reference
In-Depth Information
most integrated video adapters to 150W or more for some high-end gam-
ing video adapters, and 400W or more for extreme gaming systems with
dual or quad video adapters.
Main power connector
The original ATX specification and the ATX12V 1.X specifications defined a
20-pin main power connector, which provides power to the motherboard.
The ATX12V 2.0 specification (and later versions) expanded the main pow-
er connector to a 24-pin version that is a superset of the original 20-pin
connector. That is, the 20 original pins remain the same, and 4 additional
pins have been added to one end of the connector.
Most (but not all) current motherboards and power supplies have the 24-
pin connector. Many 24-pin power supplies use a split connector, which
allows them to function as a 20-pin or 24-pin power supply, depending on
which type your motherboard requires. Most 20-pin motherboards can
accept the 24-pin connector directly simply by allowing the extra 4 pins
to overhang the motherboard connector, but some motherboards have
capacitors or other components that prevent a 24-pin plug from being in-
serted completely into the 20-pin socket. Sometimes it's possible to bend
the interfering component slightly to provide clearance for the 24-pin
power supply plug, but 24-to-20 pin adapter cables are readily available
and a much safer solution.
Even if you use a 20-pin motherboard, we recommend buying a 24-pin
power supply.
Supplemental power connectors
Early PCs required only the main power connector to power the mother-
board and peripheral power connectors to power drives and other peripher-
als. As the power requirements of newer and faster processors and video
adapters continued to climb, supplemental power connectors were add-
ed to power supplies to meet these larger power requirements. Modern
power supplies provide the following supplemental connectors:
+12V power connector
All current ATX12V power supplies provide a four-pin (2 × 2) +12V
power connector, which connects directly to the motherboard near
the processor and provides power to the processor.
Power supplies that meet both the current ATX12V and EPS12V stan-
dards provide at least one eight-pin (4 × 2) secondary +12V power con-
nector and, optionally, a tertiary +12V power connector that uses the
same four-pin arrangement as the connector on a standard ATX12V
2.X power supply. To ensure backward compatibility with ATX12V
motherboards, most EPS12V power supplies implement the second-
ary eight-pin connector or connectors as a splittable pair of four-pin
2 × 2 connectors, either of which may be used to provide processor
power on an ATX12V motherboard.
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