Need Help with my RAM

[Nicho_Lintang]

My laptop is Lenovo B40-45 2848

I have 2GB ram but why on my laptop it is written only 1.71GB ram that can be used?

Of course this makes my laptop very slow because i use windows 10 64 bit requires at least 2GB to operate properly and Lenovo only provides drivers for windows 64bit only.
I've tried various ways to fix it like I've tried msconfig and see the BIOS settings (BIOS is very simple, nothing there).
I've also tried to reinstall my laptop with the latest version of windows 10 64bit but it keeps it that way.

Please help me to find the solution. I can't even work with the laptop because it is so slow and lagging

Spesification:
Prosesor AMD APU A8-6410 quad-core 2GHz Turbo 2,4Ghz
Chipset AMD
Grafis AMD Radeon R5
Memori RAM 2GB DDR3L
Storage hard disk 500GB

 

[rgd1101]

It using some of the ram for your iGPU

it slow because it a lowend cheap laptop

 

[rgd1101]

Look like you might be able to upgrade the ram and to a ssd
http/www.crucial.com/usa/en/compatible-upgrade-for//lenovo-b40-45