This question was asked before but was never answered.
According to reviews on Missing Remote and Anandtec back in April, the new IB processors support 23.976Hz with a 'new' BIOS and appropriate drivers.
I have a DH77EB, i3-3225
BIOS 089
Win7 Sp1 x64
Driver v 2761
latest MEI (I think 8.0 or 8.1)
I can see that screen resolution 1080p23 is offered, as well as 1080p24
However, both result in a 24.00xxHz refresh rate.
What needs to be done to get 23.97xxx (i know it won't be perfect, but at least somewhere near the ideal value).
Cheers,