Which of the following BEST describes the difference between the “baby” AT and ATX
motherboards?
A.
The “baby” AT motherboard allows for the installation of more than two full-length expansion
cards whereas the ATX motherboard allows for only one or two.
B.
The processor, memory, and expansion slots are all in line with each other on a “baby” AT
motherboard, whereas the ATX motherboard has the processor and memory slots at right angles
to the expansion cards.
C.
The ATX motherboard allows for the installation of more than two full-length expansion cards,
whereas the “baby” AT allows for only one or two.
D.
The “baby” AT motherboard has a 20-pin power connector while the ATX has a 12-pin power
connector.
Explanation:
On the AT motherboards the processor, memory, and expansion slots are all in line with each
other. Because the processor and memory were in line with the expansion slots, only one or two
full-length cards could be used. Also, the processor was far from the power supply’s cooling fan
and would therefore tend to overheat unless a heat sink or processor fan was directly attached to
it. To overcome the limitations of the “baby” AT design, the ATX motherboard was designed. The
ATX has the processor and memory slots at right angles to the expansion cards. This puts the
processor and memory in line with the fan output of the power supply, allowing the processor to
run cooler. And, because those components are not in line with the expansion cards, you can
install full-length expansion cards in an ATX motherboard machine.
Incorrect Answers:
A: Because the processor and memory were in line with the expansion slots, only one or two fulllength cards could be used. Also, the processor was far from the power supply’s cooling fan and
would therefore tend to overheat unless a heat sink or processor fan was directly attached to it.
D: The ATX motherboard has a 20-pin power connector that accepts a single power connector
while the AT motherboard has a 12-pin power connector for the P8 and P9
connectors.Reference:David Groth and Dan Newland, A+ Complete Study Guide (2nd Edition),
Sybex, Alameda, CA, 2001, p. 61