Issues w Memory use by Photoshop

[rabanito]

I observe the memory use by PS in the Task Manager (Windows 10)

After:
Open PS......................0.8GB     
Open RAW File.............2.0 GB     
Close File....................2.0 GB

Another try:
Open PS......................0.8GB
Open RAW File.............2.0 GB
Open two more Files.....2.7 GB
Close all Files...............2.7 GB

Only when I close PS is the memory free.

Before starting PS it reads 32%
When I start PS the Memory column reads 36%
With one file open it goes to 45%       
With three files open            48%     
Closing all files changes nothing. Doesn't change to 36% (like at the start)
Closing PS goes back to 32%

Am I doing something wrong?
It looks like opening files just acummulates memory but closing them have no effect

[TonyW]

I think what you are observing is correct behaviour.

AFAIK PS allocates memory as needed and once allocated is reused rather than de-allocated  and then reallocated each time it is needed.  I believe working this way leads to performance benefits within PS.

[Jeremy Roussak]

I think that's a likely explanation, particularly if you're not running other applications which demand memory. It's possible that if necessary the OS could ask PS to release memory that it's no longer actively using.

Jeremy

[rabanito]

Jeremy and Tony:
Thanks!
I learned something I didn't know