Windows 10 uses only 75% or 3/4 RAM

I didn't notice that page 3 started! If I enable paging file size on either D or E drive or both drives, then performance might improved and crashes will stop finally? By the way that I set custom size 800-800 in C drive and now crashes stopped!

Low memory warnings mean the commit charge is approaching the commit limit, which is defined a RAM size plus pagefile size minus a few MB. These warnings have nothing to do with RAM usage. For your current workload you NEED a pagefile. I would recommend one of at least 4 GB, preferably system managed. Where you put it is of secondary importance. The pagefile probably won't be used much. The commit limit is all about it's size, not how much is used.n

Allocating a pagefile is the solution to my crashes problem, but I want to know if my allocated RAM is going to be more than 3 GBs if I do this action. Remember the title of this thread is that windows 10 uses only 75% of my RAM and this is stupid and idiot.

Erez said:

Allocating a pagefile is the solution to my crashes problem, but I want to know if my allocated RAM is going to be more than 3 GBs if I do this action. Remember the title of this thread is that windows 10 uses only 75% of my RAM and this is stupid and idiot.

Will the memory gauge show more than 75% usage? Probably not. In fact it will probably be lower. And that is a good thing.

Windows 10 memory manager is highly complex and sophisticated, the product of years of research, development and testing. Unfortunately that often means it will be misunderstood and criticized by those who lack the knowledge to understand it. That includes just about everybody, including many computer professionals.

The memory gauge does not account for all memory usage. If it did many systems would show near 100% usage most of the time and that would be neither useful nor interesting. Typically most of the memory that is shown as not in use is on the standby list. You can see this in Resource Monitor. This memory acts as a kind of cache and is a major contributor to good performance. Windows will always (consistent with other requirements) try to keep this memory at a reasonably high value. In your case the memory manager doesn't consider more memory assigned to processes is warranted and is better used on the standby list. This is a dynamic process that changes according to the situation. It is also VERY complex and often misunderstood.

but if I will run many processes in the background that require a lot of memory to function, I will have to use all my RAM for them. I don't want windows 10 to restrict me and disallow some processes not running in the background.

If you run many processes the memory manager will assign them more memory, even to the point of almost 100% usage. But that would only occur under the most extreme conditions. I have seen this and it isn't pretty. Performance was terrible. Windows will not artificially restrict memory usage. With no pagefile your workload was limited by the constrained commit limit, not by RAM. Giving processes more memory would not have improved performance but would in fact have impaired it.

I have seen nothing in your description or screenshots that would indicate the memory manager was doing anything wrong. What I saw was the memory manager making the best of a very difficult situation that was imposed on it - the lack of a pagefile.