Originally Posted by glorsplitz
Thank you dr.s, burdi01, I also confirm with VB 4.3.6 r91406.
The "intel_pstate=disable" flag is no longer needed. Similarly in my Linux from Scratch VirtualBox-4.3.6 guest system, I was able to enable "CONFIG_X86_INTEL_PSTATE" in the custom-built kernel.
Here's the full list of the modifications: