Maximum Throughput of a PXI System

Updated Jan 25, 2019

Reported In

Hardware

  • PXIe-1085
  • PXIe-8880
  • PXI Chassis
  • PXI Controller

Issue Details

  • What is the maximum capacity/throughput of my PXI system?
  • I have a PXIe-1085, and I see in the specifications there are two different values for bandwidth. How can I tell if my PXIe-1085 is a 24 GB/s chassis or a 12 GB/s chassis?

Solution

For PXI systems the maximum sustainable data throughput is 110MB/s. However, streaming from RAM to peripherals can cause a drop in throughput of 20% to 40% per bridge.

For PXI Express systems the maximum throughput is limited by the number of links in the chassis and controller. For example, if your system has a PXIe-1085 24 GB/s chassis and a PXIe-8880 controller, the maximum data throughput will be 24 GB/s.

If you aren't sure whether your PXIe-1085 is 12 GB/s or 24 GB/s, you can find out by looking at the part number found on your chassis and the part numbers listed on the PXI Chassis shop page.

As you can see in the image below, the chassis backplane has one x16 Gen 3 and one x8 Gen 3 links to communicate the peripherals with the controller.  The x16 Gen 3 link contributes with a throughput of 16 GB/s and the x8 Gen 3 contributes with 8 GB/s for a total throughput of 24 GB/s.

 

 

 

The PXIe-8880 controller has two PXI Express Link configuration, one of them has a x8 Gen 3 link and a x16 Gen 3 link for a total throughput of 24 GB/s. This match with the chassis throughput allowing a maximum throughput of 24 GB/s.

 

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