Windows 10 (32 bit) is limited to 4 GB even with PAE enabled.
The official Microsoft document about client OS limitations is here.
Devices have to map their memory below 4 GB for compatibility with non-PAE-aware Windows releases. Therefore, if the system has 4GB of RAM, some of it is ...
Able to get an answer for one my question
In case available is close to 0, will it end up in a System crash?
On testing in one of my servers, where I loaded the memory with almost full as below
sys> free -h
total used free shared buff/cache available
Mem: 11G 11G 135M 25M 187M ...
Here's another answer purely about Committed_AS being lower than "expected":
The interesting lines from your /proc/meminfo are as follows:
Active: 4854772 kB
Inactive: 5386896 kB
Active(anon): 33468 kB
Inactive(anon): 412616 kB
Active(file): 4821304 kB
Inactive(file): 4974280 kB
Mlocked: 10948 kB