Look here for eplanations of the BIOS settings:
Gigabyte X48T DQ6 Living Review - Page 2 - Clunk's Forums.
Keep the RAM at 2.0D for the time being, you can always raise it later when the CPU is stable.
Try FSB 400, memory 2.0D, VCore 1.45V, loadline calibration on, PLL at 1.7V, MCH Core at 1.24V and CPU Termination at 1.4V. If that doesn't work raise CPU Temrination to 1.45V and see if that helps