I've been using my laptop again for some time (hp g72 b20sg) and when I go to the task manager it shows me that only 2.5gb RAM are used and I thought that a stick was broken, but I've also read some of the onboard graphics card is used and now I'm not sure which of the two applies. I want to upgrade the RAM to 8gb later but just want to know whether it is really broken or something else.
If your ram was broken, your pc or laptop wouldn't turn on at all. So no, it's not broken.
So just because 2.5 GB are used the RAM is not broken, but simply not used. It shouldn't be used to 100% continuously. That is rather positive that he only has 2.5. If the RAM were broken, it would usually not be possible to do anything. And the graphics card has nothing to do with it, it has its own graphics memory.
No he is not.
Depending on the number of actively running programs and the programs themselves (e.g. When playing games), more or less is used. So if your RAM is not fully used, you still have reserves. That's a good thing. But look again when you are running memory-intensive programs like 3D games, it will look completely different.
Because the shared memory (Windows 10 calls the "Commonly used GPU memory" in the GPU section), i.e. The part that the graphics card is allowed to take away from your RAM, is only used when games are actively running. As you read correctly, OnBoard graphics cards usually do not have their own dedicated VRAM and therefore have to use your RAM, which is a major weakness. Also because the shared memory is not processed quite as quickly as processes via a dedicated VRAM.
I want to upgrade the RAM to 8gb later
You absolutely should. Even 8 GB is far too little for today's programs and games, everything below that in any case. If you play 3D games occasionally, I'd go for 16GB if possible. The device definitely benefits from it. Because what you absolutely want to prevent is that your device wants to access virtual memory. Windows does this at the moment when there's not enough memory available, then it creates a file on the hard drive and stores it there. In that moment, your system becomes lame without end. In normal applications, if necessary. Still ok, but deadly when playing games or video playback.
A ram can't be recognized. Contact problem?
Rams don't break normally.
By the way. My old laptop was only 4 GB. Always got there.
