Question RAM not usable/ not showing in BIOS

Nov 29, 2023
I have a Vivobook 14 X412DA with 8gigs ram(4gb soldered+ 4gb in slot 2). I opened the laptop yesterday for cleaning and also removed the removable RAM.
When I booted into windows it showed 8gb RAM in Task Manager but only 3.4 gb as usable(before it was 5.9gb) and 4.6(approx) as hardware reserve, 2 out of 2 slots used. For gpu it was showing 512 mb as dedicated memory and 1.9 as shared memory.

CPU-Z showed 8gigs total and 2 rams.
When I checked in BIOS, it only showed 3540 RAM.
In MemTest86 it also showed 3540 RAM, but in detailed RAM info it shows both sticks( first one shows SPD not detected and second shows as detected, later learned that memtest86 cannot read SPD from soldered RAM, so I'm not sure which RAM stick is working and which is not. Never touched the soldered ram)

Already tried reattaching the RAM. There is no option to set iGPU VRAM in BIOS(searched everywhere). Saw a custom BIOS to set it higher or lower but I'm holding on it.

Any help is appreciated. Thank You.

Also, Whenever turning on the laptop, it gets stuck in loading screen( dots do not move) and is fixed for one time when I reset the BIOS settings to default. Then it goes back to being stuck the next time being started.

I noticed now that during ram test when only the soldered RAM is left on board, that works and when the other RAM is attached, that works but not both of them together.