Can a 64-bit PCI bus running at 100Mhz support four 2Gb/s HBAs? No, because the architecture only permits the connection of two devices at this speed.
A 64-bit PCI bus running at 133Mhz is a dedicated bus architecture and can only support one HBA or interface card.
How many 4Gb/s HBAs can be supported? How many 10Gb/s HBAs?
Most high-end servers that would be capable of this much throughput will probably have multiple PCI buses as well, so 64-bit 100Mhz PCI will generally meet the needs of today’s networking applications. However, it is clear that the PCI bus must evolve or be replaced to keep up with the increasing speed of processors and networks.
It’s worth noting that a 2Gb/s FC HBA is potentially capable of reading data at 200MB/s and writing data at 200MB/s - a total of 400MB/s.