Can I run games that require 8 GB RAM with 6 GB RAM and 4 GB Virtual RAM?
Honestly, it really depends on the game, but generally, if a game requires more RAM than your machine has, it's going to struggle running on your machine.
Here are possible scenarios:
- The game might refuse to install because you don't have enough RAM;
- The game might install, but then refuse to start.
- The game starts, but then has long loading times or hitching problems.
- The game starts and runs like it should, or at least at an acceptable level.
If a game has a demo or another sort of free trial available, that is usually the best way to figure out whether a game might work on your system with less RAM.
I've done some googling around for your specific case. Final Fantasy XV has a demo you can download and install from the Steam store page to see if it will work on your system. According to a Steam discussion thread, there are people that have gotten it to work on a 4 GB system, but I don't know how reliable those reports are.
If you manage to get it to work with 6 GB of RAM, it is possible that you can get problems deeper into the game, when more things need to be loaded into the game. In the end, 6 GB of RAM is well on the low end these days, so if you have any option to affordably upgrade your RAM amount to 12 or even 16 GB of RAM, you probably should.
Virtual memory is designed to help in the situation where you have multiple processes, which together require more memory than you have available, but not all at once, by swapping memory that is not currently being used to a storage medium.
It will not help in this case, where you have one process which requires more memory than you have available.