DL380G7 risers and P411

[PMac_1]

As I understand it, the DL380 G7 ships with 1x Default PCIe Riser with the following expansion options:
Expansion Slot 1 : PCIe Gen 2, Connector Width X16, Bus Width X8.
Expansion Slot 2 and 3 : PCIe Gen 2, Connector Width X8, Bus Width X4

The P411 Smart Array controller
Data Transfer Method : PCIe Gen 2, X8
Connector Width X8

If the P411 is being driven by on x4 PCIe gen 2 lanes then that's 4 x 500MB/s which is 2GB/s or 16Gb/s which appears sufficient to saturate the 2 x 6Gb/s SAS ports.

Why then does the P411 have x8 lanes?
Would any benefit occur by installing a PCI e gen 2.0 X8 riser with x8 lanes? Of using the existing X16 connector (which has x8 lanes).

Bottom line, I need maximum throughput to 2 RAID6 ADG arrays of 12 x 600Gb 10K RPM Dual Port SFF drives with a shared hot spare in a dual-domain SAS config in a D2700 - for archiving video surveillance data.