The whole Virtual memory thing is so that when the processor (brain) is doing it's thing, It might start becoming a bit full, so it passes information it's processing to the memory while it does something else, but, if the memory becomes a bit full, it then passes that information into a 'swap file' (virtual memory). The reason for Double the memory plus 11 is that the processor can work with a full memory load, and swap to a new full memory load with a minimum of time, I believe the 11 is for the registry to remain loaded in memory too.
Reason for creating a static Virtual memory: Because as windows fills the virtual memory up is re-writes the file on the hard drive, this creates pauses (sometimes substantial) while it re-creates a larger 'swap file'... once it is done with this larger file, it re-writes the file to a smaller size again.
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