This has been an often discussed issue.
Bottom line is Photoshop will take as much memory as it needs if it is available. There is no need to empty memory. It will recycle it as necessary.
Are you experiencing problems with the memory grab?
The initial memory is used by all your presets, if you have many brushes patterns, etc, and especially if you use large tiles, initial memory usage will be bigger.
Photoshop does not release the memory it already allocated in the amount you set in the preferences, so that it keeps a single block, unfragmented of memory. It is the best solution for performance.
Chris Cox, one of the key engineers on Photoshop teaches others about memory management and optimization, and he is recognized as being one of the best at it (source: AMD engineers at Photokina)
You can read some info about memory here: http://kb2.adobe.com/cps/404/kb404439.html and there: http://photoshopnews.com/2005/04/04/photoshop-cs2-how-much-ram-fact/
I guess that there is no need to translate in French, as your English seems good enough!
Photoshop CS5 memory wrote:
Under CS4 it was regularly necessary to me to relaunch the appli to empty the memory
Do you know that you can go Edit > Purge > All to reclaim that memory?
Merci pour les différentes réponses, mais cela n'explique absolument pas la différence entre CS4 et CS5. Sous CS4 je n'avais pas de ralentissements en cours de travail. Après de gros travaux je relançais l'appli pour retrouver un CS4 frais...
Sous CS5, au bout d'un moment (je n'ai pas pour l'instant délimité celui-ci) même tout en étant loin de dépasser la limite des 17 Giga, l'appli bloque momentanément, le temps de décharger de la mémoire sur le disque (mauvaise prise en compte des 17 Giga sous Vista 64 ???)
Les paramètres de Windows n'ont pas changé entre CS4 et CS5.
Je suis de langue française, mais je fais la traduction en anglais sachant que cette communauté est plus nombreuse.
Merci pour celui qui aura une piste de réponse !
Thank you for the various answers, but it does not absolutely explain the difference between CS4 and CS5. Under CS4 I had no slowings down in the course of work. After big works I relaunched the appli to find a fresh CS4....
Under CS5, after a while (I did not bound at the moment this one) even while being far from exceeding the limit of 17 Giga, the appli blocks for a moment, the time to release from the memory on the disk (bad consideration of 17 Giga under Vista 64???)...
The parameters of Windows did not change between CS4 and CS5.
I am of French language, but I make the translation in English knowing that this community is more numerous.
Thank you for the one who will have a track of answer!
If you're seeing stalls, double check your scratch disk settings (Edit - Preferences - Performance) and make sure you've got it configured to write to an internal scratch disk.
Also check your Windows event logs for the possibility of coincidental disk errors (failure). Those can cause stalls.
Is the scratch disk located on an SSD? they are blazing fast, but sometimes some did stutter.
I hope that Chris Cox will see this discussion, he might be interested in the difference of behavior.
Do CS4 and CS5 have the same plug-ins?