I'm curious whether:
Thanks in advance.
This is the list of tested components for your Intel(R) board DX79SI
http://www.intel.com/support/motherboards/desktop/dx79si/sb/CS-032973.htm# tested Intel® Desktop Board DX79SI — Tested Peripherals
I would recommend to post this information at the proper department:
750 works in DX79SR board, but no boot support, cause the whole line of Intel DX79 boards do not comply with UEFI 2.3.1 specification. Also, consider that PCIE 3.0 is not officially supported by your MB, so drive may work on 2.0 speed, with limited performance.