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Sneak Preview: Intel Alderwood/Grantsdale Chipsets

PCI-X Vs. PCI Express

Parallel PCI standards with 5 V and 3.3 V are incompatible. Whatever is electronically possible is allowed mechanically.

Source: Digi PCI Technology Overview.

When looking at the comparison table below, you might be tempted to question whether PCI-X would be rendered superfluous. While PCI Express will mainly be around in desktop systems, PCI-X will remain the prevailing high-performance interface for high-end workstations and server systems. Finally, PCI-X 1066 will be able to provide up to 8.5 GB/s.

StandardBus WidthClockTransfer
PCI 2.332 Bit33 MHz66 MHz133 MB/s266 MB/s
PCI 6464 Bit33 MHz66 MHz266 MB/s533 MB/s
PCI-X 1.064 Bit66 MHz100 MHz133 MHz533 MB/s800 MB/s1066 MB/s
PCI-X 2.0 (DDR)64 Bit133 MHz2132 MB/s
PCI-X 2.0 (QDR)64 Bit133 MHz4264 MB/s
PCI Express1 Lines, 8 Bit2.5 GHz512 MB/s
PCI Express2 Lines, 8 Bit2.5 GHz1 GB/s (Duplex)
PCI Express4 Lines, 8 Bit2.5 GHz2 GB/s (Duplex)
PCI Express8 Lines, 8 Bit2.5 GHz4 GB/s (Duplex)
PCI Express16 Lines, 8 Bit2.5 GHz8 GB/s (Duplex)
PCI Express32 Lanes, 8 Bit2.5 GHz16 GB/s (Duplex)