In most cases when I am away from home, I use the laptop in iGPU only mode. I have it running this way in both windows and linux(mostly). When I check the available VRAM for the 780m when running in iGPU only mode it is limited to 512MB. This post is here with the hopes that someone at Asus will see this and potentially expose the BIOS options to set the system memory that the iGPU is able to address. My model has 32 GBs of ram and I am willing to give the iGPU more than 512MB.