Okay let's take a step back
1) you have 8GB of RAM installed based on RM (Resource Monitor)
2) Almost every board has video built on, so right off the bat based on your UEFI/BIOS setting that will reduce it by about 1256 (1.2GB) RAM to set aside for video display. If you did reduce it down to 256MB, that will help, but if you just disabled it the RAM is still used because your CPU has the GPU built in (Normal for iCore, APU, etc.)
3) As noted in my previous post the top 3 programs running FireFox + BitDefender + Desktop Window Manager is almost another 1GB
4) Then add in all the other little things like like your desktop, running the NVidia Apps, etc. basically "Make Windows RUN" is unfortunately in a constant state of flux. So while...