3897292 seems to be the 4 gbs of ram minus the ram used by the video card, around 200 mbs
if this kernel is stable for you and video card remains working the way you need it, then you could consider in a couple weeks to remove other kernels
most users keep two installed, the original one and the latest stable, you can keep more than 5 but there is no use for more than two
"There is no video card, Per Se. It's all integrated into the board"
you have a video card but it is not integrated into the mainboard, it is integrated inside the cpu
in laptops this is the way you have video cards now, the other way is to have a full size laptop video card that uses lots of watts per hour making the battery charge last alot less