Why is your ram 384Mb original is 512Mb

That pretty much means that You have a graphics card that shares its memory with global memory (ie. doesn't have any of its own). This happens on most Intel integrated video cards that claim to support games but really don't.

The difference between 512 and 384 is 128MB, and that's how much Your video card is taking 'as its own'. You can't do much about it (except maybe change the amount in BIOS - I don't recommend it without a bit of knowledge though).

If You want to play gpu-intensive games, then my advice would be to get a real graphics card.