简单来说，PCI-x有1.0b和2.0两个标准，1.0b兼容32位宽和64位宽，工作在64位下，带宽就是133MHz * 64Bit = 8Gbit/s
2.0标准带宽是1.0b的四倍，即最高在32Gbit，可以插Infinband的30G的网卡了
PCI-X builds on the industry-standard PCI foundation, adding greater
performance for today's demands. PCI-X is currently available in two
versions: PCI-X 1.0b and PCI-X 2.0. Both are backward compatible with PCI
standards.
PCI-X 1.0b runs at up to 133 Mhz at either 32- or 64-bit widths. It brings
throughput up to over 8 Gbits/sec.
PCI-X 2.0 takes this technology even farther, offering four times the
bandwidth of PCI-X 1.0b without increasing pin count. It is an ideal
technology for server cards for Fibre Channel, RAID, high-speed
networking, Infiniband™, SCSI, iSCSI and other demanding technologies.
2.0标准带宽是1.0b的四倍，即最高在32Gbit，可以插Infinband的30G的网卡了
PCI-X builds on the industry-standard PCI foundation, adding greater
performance for today's demands. PCI-X is currently available in two
versions: PCI-X 1.0b and PCI-X 2.0. Both are backward compatible with PCI
standards.
PCI-X 1.0b runs at up to 133 Mhz at either 32- or 64-bit widths. It brings
throughput up to over 8 Gbits/sec.
PCI-X 2.0 takes this technology even farther, offering four times the
bandwidth of PCI-X 1.0b without increasing pin count. It is an ideal
technology for server cards for Fibre Channel, RAID, high-speed
networking, Infiniband™, SCSI, iSCSI and other demanding technologies.