So I have an Asus laptop primarily for gaming and was having some FPS issues. When I looked in my system information it says that:
Installed RAM: 4.00 GB
Total Physical Memory: 3.93 GB
Available Physical Memory: 1.56
also i have an ATI 5730 HD 1GB
I read that people usually have it say "Available Physical Memory: 3.6" so I'm not sure why mine is so low. I've seen it in my games as well (Skyrim and Kingdoms of Amalur) which are always capped at 30 FPS no matter that I'm looking at. I think it's capped since it will literally show no higher fps then 30 even when staring at a wall...
I've updated all my drivers and cleaned my RAM, registrar, etc. but still shows such a low physical available memory. I even went into my msconfig and turned off anything I didn't need (some I had no idea what they did).
"Total Physical Memory" is 3.93GB, because some device (most probably the integrated video card) reserved a little chunk for itself.
"Available Physical Memory"'s definition (quote from the above link): Amount of memory (including standby and free memory) that is immediately available for use by processes, drivers, and the operating system
So it means that your system currently uses 3.93-1.56=2.37GB memory. That is 60.45% , which is pretty close to the 56%, and it keeps changing all the time.
In Task Manager go to Processes tab, and order the table by memory usage by clicking the column header. Can you see, what process use how much memory? (You may need to check the checkbox below for showing all users's processes.)
As for the constant 30 fps, I think it's set somewhere in the game. It's very common to have a setting for maximum fps, so that the computer use less electricity, and because the human eye can hardly make any difference beyond 30 fps.