Do PCI-e riser cards introduce a lot of latency?

[thilanliyan]

Do PCI-e riser cards introduce too much latency?

 

[ViRGE]

Since they're just mechanical devices, I doubt it.

 

[Keysplayr]

As long as the riser card has only 1 device installed, it should not introduce any latency. But if you perhaps were to install two or more devices into the riser (some PCI risers I used to see had 3 slots available in them for low profile (3U) rack servers), then I could see latency being introduced as they would need to share the bandwidth of one slot.

Here is a little bit about it:

Link

 

[Zap]

Originally posted by: keysplayr2003
Here is a little bit about it:

Link

Interesting link. With converting from one interface to another, besides losing some performance I'd be a bit more worried about the bandwidth of the slowest interface. For instance, I have benchmarked the same GPU using both PCIe and PCI interfaces (8800 GS, PCI version uses a bridge chip) and the PCI version was definately slower, but I believe most (but not all) of that performance loss due to the PCI bus (versus native PCIe) and not from any introduced latencies.

 

[thilanliyan]

Originally posted by: keysplayr2003
As long as the riser card has only 1 device installed, it should not introduce any latency. But if you perhaps were to install two or more devices into the riser (some PCI risers I used to see had 3 slots available in them for low profile (3U) rack servers), then I could see latency being introduced as they would need to share the bandwidth of one slot.

Here is a little bit about it:

Link

Thanks for the link.

 

[Keysplayr]

Originally posted by: Zap

Originally posted by: keysplayr2003
Here is a little bit about it:

Link

Interesting link. With converting from one interface to another, besides losing some performance I'd be a bit more worried about the bandwidth of the slowest interface. For instance, I have benchmarked the same GPU using both PCIe and PCI interfaces (8800 GS, PCI version uses a bridge chip) and the PCI version was definately slower, but I believe most (but not all) of that performance loss due to the PCI bus (versus native PCIe) and not from any introduced latencies.

Oh absolutely. Any of these modern cards would be starved with the old PCI standard. Makes perfect sense that it would be slower than PCI-e, or even an AGP variant.

 

[Keysplayr]

Originally posted by: thilan29

Originally posted by: keysplayr2003
As long as the riser card has only 1 device installed, it should not introduce any latency. But if you perhaps were to install two or more devices into the riser (some PCI risers I used to see had 3 slots available in them for low profile (3U) rack servers), then I could see latency being introduced as they would need to share the bandwidth of one slot.

Here is a little bit about it:

Link

Thanks for the link.

:thumbsup: