See the following thread: IGD Aperture Size and IGD Minimum Memory May Freeze Windows 10 and please read the answer in this link: Frequently Asked Questions for Intel® Graphics Memory on Windows® 10 and may be you will find an answer to your question.
thanks for the answer, I now understand that the settings are not really useful in my case because windows will take over the memory allocated to the graphics card.
However, I still do not understand why these values have changed following the update of the bios.
in any case thanks for the help, I will close the thread.
have a nice day