Make sure you have these set on the bios 
set VTd INTEL VIRTUALIZATION to DISABLE.
set ONBOARD AUDIO/SOUND (AZALIA) to DISABLE.
set IEEE1394 to DISABLE.
set PCI-E SUBSYSTEM/LANES to x8/x4/x4
set ONBOARD GRAPHICS to DISABLE. (optional depending on OS you running)
set PCI-E GENERATION to GEN2.
set CPU FREQUENCY SCALING to DISABLE.
set CPU PERFORMANCE MODE to ENABLE.
set FAST BOOT to DISABLE.
set CSM to ENABLE.
set VTd INTEL VIRTUALIZATION to DISABLE.
set ONBOARD AUDIO/SOUND (AZALIA) to DISABLE.
set IEEE1394 to DISABLE.
set PCI-E SUBSYSTEM/LANES to x8/x4/x4
set ONBOARD GRAPHICS to DISABLE. (optional depending on OS you running)
set PCI-E GENERATION to GEN2.
set CPU FREQUENCY SCALING to DISABLE.
set CPU PERFORMANCE MODE to ENABLE.
set FAST BOOT to DISABLE.
set CSM to ENABLE.
Tried almost everything you said. Couldn't find the IEEE1394 option, also couldn't find the 8x/4x option for the lanes and CPU frequency scaling. The rest is like you sugested.