How much memory is Firefox really using?

How come the the Memory Column of the Process tab of Task Manager shows
that Firefox is using 1,140 Megs of memory, and that 78% is being used
in total.

but at the same time, the memory section of Resource Monito**r says
Firefox is using 1,620 Megs of memory, and Used Physical Memory is also
78%?

Without touching anything in FF, I can go back and forth between the two
screens and for a while they both stayed the same but then the first one
dropped to 980, but the second one stayed the same.

Why aren't the two screens the same and which is right? I guess the
bigger one has to be right but why is the smaller smaller?


**It's usually about 2000, and one loan occasion it was 3500.

micky wrote:

How come the the Memory Column of the Process tab of Task Manager
shows that Firefox is using 1,140 Megs of memory but at the same
time, the memory section of Resource Monitor says Firefox is using
1,620 Megs of memory

You're seeing the difference between private, shareable, committed and
working set.

micky wrote:

How come the the Memory Column of the Process tab of Task Manager shows
that Firefox is using 1,140 Megs of memory, and that 78% is being used
in total.

but at the same time, the memory section of Resource Monito**r says
Firefox is using 1,620 Megs of memory, and Used Physical Memory is also
78%?

Without touching anything in FF, I can go back and forth between the two
screens and for a while they both stayed the same but then the first one
dropped to 980, but the second one stayed the same.

Why aren't the two screens the same and which is right? I guess the
bigger one has to be right but why is the smaller smaller?

**It's usually about 2000, and one loan occasion it was 3500.

Well, what is the *title* of the memory column you are looking at in
Task Manager? Is it just "Memory - Private Working Set"? Did you
configure Task Manager to also show the "Memory - Working Set"? You
don't say which memory type is displayed in your Task Manager.

http://getgreenshot.org/2010/07/24/a...e-working-set/

micky wrote in
:

How come the the Memory Column of the Process tab of Task Manager shows
that Firefox is using 1,140 Megs of memory, and that 78% is being used
in total.

but at the same time, the memory section of Resource Monito**r says
Firefox is using 1,620 Megs of memory, and Used Physical Memory is also
78%?

Without touching anything in FF, I can go back and forth between the two
screens and for a while they both stayed the same but then the first one
dropped to 980, but the second one stayed the same.

Why aren't the two screens the same and which is right? I guess the
bigger one has to be right but why is the smaller smaller?


**It's usually about 2000, and one loan occasion it was 3500.

It depends on which version of Firefox you are running as well. They are
migrating to a two process structure from their current single process
model. That can make a difference in how the usage is measured. Also,
unless both montoring processes are getting their data at the exact same
time, there will be differences as well. The important part is 'is the
memory usage climbing when I think it should be stable or decreasing?' I
stopped using 32bit Firefox when I determined that there was a memory leak
or some such so that the memory in use always increased and never
decreased. I usually had to stop and restart Firefox every few days to get
the memory in use down. 64bit Firefox doesn't have that problem.