I put in a service request for this, but I'll also post here.
We're looking at getting our PXI chassis to talk 10GbE Ethernet, which the
PXIe-8238 provides. However, to get full bandwidth, the specs say that it
needs a Gen2 x8 PXI connection. I need to know if our current chassis and
controllers will support this. We currently use PXIe-8840 controllers and
PXIe-1065 and PXIe-1082 chassis. Will we need to upgrade in order to get full
10Gb bandwidth? What would the bandwidth likely max out at if our current
hardware doesn't do Gen2 x8 PXI?
Is there an easy resource that describes these capabilities on NI's website somewhere?
Both chassis you listed have Gen2 x4 connectors. This can be found in the user manuals for both chassis on page 1-2 (that's "chapter 1, page 2" not "pages 1 through 2") under "Key Features."
Looking at other chassis, it looks like the current options for Gen2-x8 PXIe chassis are the 1085 and 1086 (the 1085 also has a 24 GB/s model with Gen3-x8 connectors).
Gen2-x4 PCIe is specified to transmit at 2 GB/s, and Gen2-x8 at 4 GB/s. As such, you could expect the 8238 module to reach about half its max throughput.
PXIe-1065 is Gen 1 x4
PXIe-1082 is Gen 2 x4
PXIe-8840 max bandwidth per slot is Gen2 x4 (for a 4 link chassis, which the 1065 and 1082 are)
Many factors affect system performance, but if everything is working well 80% is a good guess on the available bandwidth.
Gen 1 x4 ~ 800MB/s
Gen 2x4 ~ 1.6GB/s
10G Ethernet is ~1.25GB/s per port
The 1082 & 8840 will probably work decently for one port at full speed.