[mothered]

when i was buying laptop online there no such thing to select ram like 8, 16 , 32 . it was  only 8gb . i think i should purchase from amazon they alway give option when buying . they have option for selecting ram . in 8gb half ram eaten by the windows and some apps. the more higher windows version i see the more ram they eat. i have win7 4gb ram hardly use 1gb ram not much but in win10 4gb around....  

8 GB In today's computing Is not enough.

If you're anything like myself and leave your laptop running 24/7, as well as multitask with VMs and 50+ browser tabs open, It'll chew the entire memory In no time at all. If your MOBO can accommodate It, Install an additional 8 GB.

I have 4 ram slots total ? i though i have 2 only 16gb+16gb

You obviously have 1 x 8 GB stick Installed, leaving 3 slots available. The question Is, does the MOBO accommodate a maximum of 32 GB (2 x 16 GB) or 64 GB (4 x 16 GB)?

Here's a visual of my laptop. I have 32 GB running, with 2 slots not In use. It can accommodate 64 GB- which I'll be purchasing another 2 x 16 GB.