Sometimes, users come across situations where they need to allocate specific physical and virtual memory to the machines having higher configurations of memory. By following some simple steps, one can assign specific physical and virtual memory for a period of time so their requirements are met.

Assigning Physical Memory (RAM)

1. Suppose user requires 8GB of physical memory and the available machine has 16 GB physical memory. Follow steps below:    
> Open command prompt window from start menu.    
> Type “bcdedit /set removememory 8192”    
> Press Enter.

Reboot system for changes to take effect. Go to computer properties and check memory status. Although installed memory is 16GB, usable is around 8GB.

3. In order to get back the removed memory, type following command in command prompt window:
>   “bcdedit /deletevalue removememory”
> Press Enter.

4. Reboot system for changes to take effect. Go to computer properties and check memory status. Installed and usable memory should be now 16GB.

Assigning Virtual Memory

1. Virtual memory for your computer is hard drive space used by Windows when it fills up the physical RAM. Let’s say you have a computer that has 1 GB of RAM and you’re running several applications at once that might need a total of 1.5 GB of memory. Windows will fill up the 1 GB and then uses the free space on the hard drive to store the rest. This is called the paging file or virtual memory and Windows will increase and decrease the size of this file as needed. Writing to disk takes much longer than writing to physical RAM, so when Windows uses the paging file, computer performance degrades. 
   
   
2. That’s why you’ll always hear people asking if you have enough RAM because the more RAM you have, the better your computers’ performance will be. However, we can tweak the virtual memory settings so that the paging file does not get fragmented and so that Windows does not have to grow or shrink the size of the paging file, both of which will cause the computer to slow down, especially on older machines.
   
   
3. By default, Windows uses the boot partition (the partition that contains your operating system files) and it is recommended to set the size of the paging file to 1.5 times the amount of RAM that you have. 
   
   
4. To change the virtual memory settings, follow steps below:
   Go to Start > Right click on Computer > Properties.
   Click on the Advanced System Settings option.
   In the Advanced tab, click the Settings button in the Performance section.
   Go to Advanced tab in this new window.
   Click Change under the Virtual Memory heading. Below window appears:

5. Select Custom Size. Now, in the Initial Size box, enter a value equal to one and a half times the amount of the computer's installed RAM.

6. In the Maximum Size box, enter a value equal to twice the amount of the Initial Size value.

7. Click Set, and then click OK to close the Virtual Memory dialog box.

8. Restart machine to take changes into effect.

Note:

1. User must have Administrator privileges to be able to perform above operations.
2. This method works on Windows 7.
3. To check details about total and available memory of your machine, type enter 'msinfo32' in search window of start menu.