Available ram setting in photoshop cs5 / cs6 / cc

Question

hello,
i would like to know if the ram setting slider in photoshop preferences/setting is meant to be for all
the available ram in the computer or all available ram, which stays free from all other sametime running apps?
for example, if i run osx 10.8 or 10.9, i use to run ONLY photoshop and no other app besides, so the
finder would need maybe 2 or 3 GB RAM, and the rest is for photoshop.
does the ram setting count with finder ram consumption or without?
my imac has 32GB RAM - so, if i set ram to 70% (out of 32GB) in photoshop settings, the finder can use 30% of 32GB, yes?
anyway, it wont show "available ram is 32GB" in the settings, it shows less than 32GB would be available, so
is this the answer to my question?
could i set it to 80% or 90%, when i only run photoshop (cs5 / cs6 / cc) and no other app besides? (only the 10.8.5 or 10.9 finder)
or would this mean performance lags in photoshop?
thanks!

Answer 1

I would go with the suggested ram settings in the memory slider. Going over can affect other programs other than the finder and in my experience, I have never seen much of a benefit.
You have 32 GB so you can give it a try and if you run Mt. Lion,look at the Activity Monitor and see how it affects the memory allocated to the system.  Look at your Page outs to Page ins. Page outs should be 20% or less of Page ins. Some prefer 5%. The less the faster your machine will perform.
Gene