Question : Problem: Curious about 1.0 Gbps NIC on PCI interface (even PCIe-1X) & achieveing gigabit speed

So I'm fairly curious abou this...

We have a mix of workstaion with embedded gigabit NICs compared with 100 Mbps NICs. I was looking to upgrade the non-gigabit ones with PCI gigabit cards. Now doesn't the standard PCI slot only give you 133-256 MB/sec? while gigabit = 1,204 MB/sec? So in theory gigabit networking is not even obtainable. The workstations in question are Dell Vostro 200s.

Then I thought OK, why not use the PCIExpress-1x slot... but then remembered 1 lane speed only equals 250 MB/sec right? So then I got to more thinking what the @#$(*! is the point?

So anyone have any suggestions?

1 final question - what is the through throughput/bandwidth of an embedded NIC? Such as Intel Gigabit NIC on a Dell OptiPlex, etc.?

Answer : Problem: Curious about 1.0 Gbps NIC on PCI interface (even PCIe-1X) & achieveing gigabit speed

PCI Express is the new serial bus addition to the PCI  series of specifications. How ever the electrical and mechanical interface for PCI Express is not compatible with the PCI bus interface. This is a serial bus which uses two low-voltage differential LVDS pairs, at 2.5Gb/s in each direction [one transmit, and one receive pair]. A PCI Express link is comprised of these two unidirectional differential pairs each operating at 2.5Gbps to achieve a basic over all throughput of 5Gbps [before accounting for over-head]. PCI Express uses 8B/10B encoding [each 8 bit byte is translated into a 10 bit character in order to equalize the numbers of 1's and 0's sent, and the encoded signal contains an embedded clock]. PCI Express supports 1x [2.5Gbps], 2x, 4x, 8x, 12x, 16x, and 32x bus widths [transmit / receive pairs]; 2.5Gigabits/second per Lane per Direction. The 8B/10B changes the data transfer numbers to 250MBps per lane, raw data [B= Bytes, b=Bits]. The reduction in throughput is accounted for under the protocol section.


while onboard nic provide speed of pci-express as well thats mean it give you 1Gb speed.