Question 2gb of ram usable out of 8

[FilmCraft]

A few days ago I got a problem that only 4gb of ram is usable. I tried a few methods to fix it, and ended up with only 2gb available.
What.

 

[RealBeast]

Can you post some more details, like what motherboard and memory stick models are you using? Also, what fix it methods?

 

[FilmCraft]

I have no idea what is the motherboard/the ram sticks.
But I know my laptop is Lenovo Ideapad 310-15isk.