Now go to Excel and minimise it. Recheck your windows task manager and check the amount of RAM being used by Excel.exe. Shocked? Its three times less and so is the CPU Usage. Readings for Memory usage going down to 4.424K and CPU usage falling down to 16%. Check the figure below which shows the same.
Just proves that if we minimise the applications that are not being used at that time, by clicking the (-) minimise button on top right of the application, we can increase the amount of available RAM by a huge margin. Infact depending on the applications open, the difference can be as much as 30-60% percent of extra RAM. When we minimise an application it indicates that it won't be utilized by the user right now. Therefore, the OS automatically makes the application use virtual memory & keeps minimum amount of the code in physical RAM.