You will see bus architectures on the A+ Certification Exam. Another term for the expansion slots on a computer’s motherboard is bus slots. A number of different bus architectures have been developed over time. For the A+ Exam, you need to be able to identify the differences between each of these bus architectures and know which ones are more popular today.

Architecture Bus Width
(In Bits)
PCI 32/64 33 MHz
AGP 32 66 MHz (1x), 133 MHz (2x), 266 MHz (4x), 533 MHz (8x)
PCMCIA (laptops) 16 33 MHz
PCI-X 32/64 66/133/266/533 MHz
PCIe Serial Uses multiple lanes with each lane carrying 250 MBps. As an example, a PCIe x1 slot can carry data at 250 MBps, while a PCIe x4 slot can carry data at 1 GBps. PCIe version 2 doubles those transfer rates.
miniPCI 32 33 MHz