(PCI-SIG, Beaverton, OR, www.pci-sig.com) An industry consortium founded in 1992 that owns and maintains all PCI technologies. It also sponsors workshops and technical conferences. Standing for PCI Special Interest Group, more than 900 member companies are involved. Following is a comparison of PCI bus speeds. See PCI, PCI-X and PCI Express.

 BANDWIDTH OF PCI-SIG TECHNOLOGIES
 This data courtesy of PCI-SIG.

       Year  Bus Size Clock       Date Rate
 Ver.  Intro (bits)   Speed       MBytes/sec
 
 PCI - Parallel Shared
 1.0  1992  32        33 Mhz      133
 2.0  1993  32/64     33 Mhz      133/266
 2.1  1995  32/64     66 Mhz      266/533.3
 2.2  1998  32/64     66 Mhz      266/533.3
 2.3  2002  32/64     66 Mhz      266/533.3

 PCI-X 1.0 Parallel Shared
 66   1999  32/64     66 Mhz      533

                                  Data Rate
                                  Gbytes/sec

 PCI-X 1.0 Parallel or Shared or Point-to-Point
 133  1999  32/64     133 Mhz     .5/1.06

 PCI-X 2.0 Parallel or Point-to-Point
 266  2002  16/32/64  266MTs      .5/1.06/2.13
 533  2002  16/32/64  533MTs      1.06/2.13/4.26

 PCI Express (PCX) - Serial Switched Point-to-Point
      2002      x1   "2.5 Gbps      .5
      2002      x2    per          1.0
      2002      x4    lane         2.0
      2002      x8    per          4.0
      2002     x16    direction"   8.0
      2002     x32                16.0


 MTs = megatransfers per second (see MT/sec).
 Megatransfers are used when megahertz is not
 accurate (not actual clock cycles).
 PCI-X 266 is running at 133 MHz, but data are
 double clocked.  PCI-X 533 is quadruple clocked.