Hello Adnan efe ustaoglu and welcome to the Microsoft community!
According to your feedback, you are experiencing the problem of adding 16G ram to a computer that has 8G ram.
Let me explain, if you don't unplug the original 8G ram, your 16G ram will be downclocked if you plug it in.
In other words, the 16G ram you add will be forced to work at 8G for the computer.
Therefore, it may cause problems, so it is not recommended.
There may be some settings that can solve this problem.
But this computer's bios is designed and installed by each brand.
Not Microsoft, each brand of computer bios has its own design
So it's different from each other
And we don't know much about the internal settings.
That said, I have a desktop ROG computer, and yesterday I had a problem with random freezes for 2-3 seconds.
But I didn't pay attention to the issue because he just showed up once
After seeing your feedback, I remembered that I also had this problem with my computer
I unplugged the memory stick myself.
So you can check to make sure that the memory stick is not loose.
Because the connection between my memory stick and my computer is a bit loose, and it might be a problem because it is always recognized repeatedly.
Also, my own memory stick was recently tested to be defective.
I haven't had a chance to replace it yet, but you can take a look at it, and if you can't, you can use an eraser or something like that to wipe the gold finger of the memory stick.
I'm going to go back to my computer today and see if there are any clues.
I'll also share this with you, and finally, it's a good idea to get back to ASUS support at the same time.
Because this is a hardware and bios issue.
I hope you find the above information helpful
Kirito|Microsoft Community Support Specialist