As for available memory, as the name implies, you are the memory you can use. Obviously, not all the memory installed in the computer can be used by you to run the programs you open. Because the operating system also takes up memory, other background running, startup and various processes, including various applications you open, such as QQ, PS, web browser and so on. , all occupy memory. In this regard, you can open the Task Manager and look at the contents under the "Process" and "Performance" tabs. So the available memory displayed by PS is not all the memory in your computer, but the memory you have left at present, which can be used by PS. Understand? However, from 3.49GB of memory displayed in your system properties to 1.674GB of memory displayed in PS, your various programs occupy nearly 2GB of memory, accounting for 52%, which is a bit too much. You need to clean up the memory. It is best to keep the available memory above 60%, and it is best to reach above 80%. PS CS5 can clear the memory. There is a "clean" command under the edit menu, which is to clean up the memory occupied by PS, but use it with caution, because after cleaning up, all your history is gone.