Why is there not enough memory if there are almost 4GB free?

Question

Windows

The topic is about a laptop running Windows 10.
Before the update it had 4GB of memory, everything worked quite well, but I wanted more memory. And so I bought a bar, installed it, but there is still not enough memory. Those. for example, when a lot of tabs open in Google Chrome (there really are a lot, especially if these are pages with Youtube videos) + open Sublime Text + a couple of consoles + all sorts of servers in the background (mysql, postgres, apache), then the system reports a lack of memory or even cuts it down Chrome. I open the manager, and it still has 3.7GB of free physical memory.
Feeling that the second bar is not involved at all or something is configured incorrectly. Tried swapping them. Though storage is defined normally. What you should pay attention to? Prompt, who well understands with iron. Thank you!

Answer 1

Why is there not enough memory if there are almost 4GB free?

Possibly paging is turned off, and therefore it is not enough.

the system reports a lack of memory or even cuts down Chrome

At the moment, 8GB is the minimum amount of memory with which you can generally work comfortably. This is quite enough for office work - an office suite and unpretentious work with a browser.
If something is heavier, or you like to open a lot of tabs, 8GB is extremely small.

Feeling that the second bar is not involved at all or something is set up wrong

Where does this feeling come from?

I open the manager, and it still has 3.7GB of free physical memory.

Can you screenshot where 3.7GB is shown and what is the size of the swap file?