Setting a hard limit is only applicable if trying to trick software or game that requires a certain amount to run, that is all. Igpu will use as much vram it can, yes it is unlimited to it's capabilities and available ram. Ideally, unless software/game requires certain amount, youd set vram in bios to low as possible so more ram is accessible for other things.
Hello boju, sorry if I didn't understand you but what you're basically saying is that it won't help my gaming perfomance to become better? My games run really really bad now... even old games I have to run on low settings to be able to play. Does it make sense if I have 16gb RAM?