How much memory do I need to simulate instruments with high precision ?

Hi to everyone!!
I trying to calculate how much memory and processing power I need to simulate each analog parts. I thinking that a graphics card with 4 gb VRAM and use the VGA or equivalent to simulate analog parts. I thinking that just use USB is too weak. What do you think ?

I mean for example the feet altitude with 1/10 increments each kilometer require a bit above 492120 roughly 480 MB RAM just of that ?