Nelze.
Zjednodušeně:
1. je pevně nastaveno/alokováno kolik místa systémové(RAM) paměti může IGP obsadit.
(takže velikost/zvyšováním systémové do toho nemá co kecat)
2. je dynamická automaticky se mění dle potřeby GPU

What is the Intel® Dynamic Video Memory Technology (DVMT)?
Intel® Dynamic Video Memory Technology (DVMT) is a method for dynamically allocating system memory for use as graphics memory to balance 2D/3D graphics and system performance. If your computer is configured to use DVMT, graphics memory is allocated based on system requirements and application demands (up to the configured maximum amount). When memory is no longer needed by an application, the dynamically allocated portion of memory is returned to the operating system for other uses.