Even if your BIOS has the option it's only the 'initial' amount dedicated. It will still change as you load graphics intensive stuff.
Intel drivers are supposed to handle this dynamically.
There is a way to make the driver 'report' a certain amount of video RAM to programs/games but that still doesn't mean that that is what will be used. See here - https/communities.intel.com/thread/85267
Your BIOS may have an option to set aside more RAM for video. Your video hardware is built into the CPU, it does not have it's own RAM, it's shard with the main system.
Even if your BIOS has the option it's only the 'initial' amount dedicated. It will still change as you load graphics intensive stuff.
Intel drivers are supposed to handle this dynamically.
There is a way to make the driver 'report' a certain amount of video RAM to programs/games but that still doesn't mean that that is what will be used. See here - https/communities.intel.com/thread/85267