The sizing of a paging file is usually dependent on the amount of physical memory installed, which you do not indicate in your question. Maximums can be set according to the amount of disk space available and their placement. Sometimes you can set the maximum much higher than would be used by the operating system, leading to wasted allocation of disk space.
From TechNet: Set the Same Initial and Maximum Size Setting the paging file's initial size and maximum size to the same value increases efficiency because the operating system does not need to expand the file during processing. Setting different values for initial and maximum size can contribute to disk fragmentation.
In order to prevent page file fragmentation.
Maximum size.
boot partition
By default partition 0.
Paging file is located in the root folder of the system drive.
It can as much as you want, you should just have enough space on your hard drive in order to save the paging file (virtual memory file).
Paging File
How to manually change the size of the virtual memory paging file You must be logged on as an administrator or as a member of the Administrators group to complete this procedure. If your computer is connected to a network, network policy settings may also prevent you from completing this procedure. 1. Click Start, click Run, and then type sysdm.cpl in the Open box. 2. Click the Advanced tab, and then click Settings under Performance. 3. Click the Advanced tab, and then click Change under Virtual memory. 4. Under Drive [Volume Label], click the drive that contains the paging file that you want to change. 5. Under Paging file size for selected drive, click Custom size, type a new paging file size in megabytes (MB) in the Initial size (MB) or Maximum size (MB) box, and then click Set.
The "paging file" is already a form of virtual memory. There is no way to use a paging file in the same way as you would normal RAM, as hard drives are hundreds of times slower than RAM.
Do you mean RAM? Or the paging file?
This question answers itself. It takes time to retrieve information from the paging file on the hard drive.