The RAM Meter module is useful, shows RAM usage in real time. However, the value shown is not so practical; only the physical RAM is de-facto usable, page file is slow.

Physical RAM usage is more meaningful I guess, the committed value is unreal. For example in the screenshot below, the value shown by RAM Meter is higher than physical RAM installed:

Actually the opposite is true: physical RAM usage is pretty much meaningless, because unused RAM is wasted RAM. As such, all RAM is used for caches etc... - you could say physical RAM is always 100% in use. You also won't run out of memory until you run out of BOTH physical AND virtual memory.

Also, applications unused for a while may be paged out to disk, but they are still using memory in your system (even if most of it is paged out of physical RAM).

Personally I still prefer thinking of the physical RAM limit, coz page file on disk is usually with perfectly slow access speed.

That would be great if there could be 2 options for the value shown in RAM Meter: (1) physical only, or (2) physical+virtual