3 series of tests on Intel R2216GZ4GCLX server show maximum read speed about 2.8Gbyte/sec, then theoretical maximum is 6Gbyte/sec (6Gbit/s per port, 8 ports)
Drives: 10 Intel SATA SSD 730 240Gb (520Mbyte/sec sequential read)
Mainboard and SAS controller has latest firmwares, PCIe Gen3 enabled in BIOS.
Testing sequential read with 256K blocks, 64 outstanding I/O (iometer, SQLIO), Win2012R2, LSI drivers 6.708.7.0, 10 drives with SAS Expander and 8 drives direct controller to backplane.
1 drive - 520Mbyte/s, 2 drives - 1025, 3 - 1535, 4 - 2040, 5 - 2550, 6 - 2800, add more drives do not increase transfer speed.
Any ideas about bottle-neck?