GT 540M recognised with 384 vram. How to increase it to its default 1GB?

Hello! I recently successfully installed Mac OS Sierra on my Toshiba laptop (P755 10D). All works well except for the fact that my video card - Nvidia GT 540M is recognized with just 384 vram although it has 1GB. I used this kext that made the OS recognise my hard as GT540M and not HD 3000 see the image -> https://ibb.co/djYMaF . Does anyone know how I can increase the video ram? f