You shouldn't need to 'allocate' any memory to the IGP since the drivers for modern IGPs automatically resize the IGP's memory pool to accommodate whatever demands are put on it up to the size limit.
You shouldn't need to 'allocate' any memory to the IGP since the drivers for modern IGPs automatically resize the IGP's memory pool to accommodate whatever demands are put on it up to the size limit.
even if you could, most IGPU / onboard graphics aren't powerful enough to even use all of it, so it would have zero benefit and could simply leave far less RAM for your main OS to use for regular program stuff.