Posted by Unknown | Posted in Windows | Posted on 12:26 PM
From RAM To Hard Disk To RAM?
The purpose of a paging file is to create virtual memory for situations where there is not enough system memory. Virtual memory serves as an emergency source of additional memory, only to be used when there is not enough system memory.
The RAM drive, on the other hand, is used to create a very fast pool of temporary storage space in the system memory. It ties up system memory, so it is usually created when there is a lot of free system memory. Even then, it is usually kept small and only used to store temporary work files.
Therefore, does it make sense to use limited system memory to create a RAM drive that is used to service the paging file? No, it doesn't make sense at all.
Remember, most paging files are very large, a few hundred megabytes to a gigabyte in size. Most computers even come with enough memory to create such a large RAM drive, much less move the entire paging file to the RAM drive.
Even if you have a lot of system memory, creating a large RAM drive reduces the pool of available system memory. This increases the need for virtual memory which means more data will have to be paged out into the paging file. This increases the size of the paging file which will inevitably be much larger than the RAM drive.
At this point, Windows will automatically create more virtual memory via a dynamic paging file. Because a large portion of the system memory has already been taken up by the RAM drive, this will cause a lot of data to be paged out to a large dynamic paging file on the hard disk. That defeats the purpose of moving the paging file to the RAM drive - improved performance.
If your system has a lot of system memory, don't waste your time creating a RAM drive to service the paging file. If there is a lot of free system memory, Windows will not need to page out data to the paging file. That would produce the best results. Nothing is faster than running the programs directly in system memory.
Reducing Reliance On Virtual Memory
Windows can get too enthusiastic about paging data out to the paging file. This can lead to unnecessary paging, even when there is a lot of free system memory.
Luckily, we can do something about this :-
+ Enabling the Pagefile_Call_Async_Manager service (Windows 98, Me)
+ Stop NTExecutive from paging (Windows NT, 2000, XP and above)
We will take a look at each and see how they work.
The purpose of a paging file is to create virtual memory for situations where there is not enough system memory. Virtual memory serves as an emergency source of additional memory, only to be used when there is not enough system memory.
The RAM drive, on the other hand, is used to create a very fast pool of temporary storage space in the system memory. It ties up system memory, so it is usually created when there is a lot of free system memory. Even then, it is usually kept small and only used to store temporary work files.
Therefore, does it make sense to use limited system memory to create a RAM drive that is used to service the paging file? No, it doesn't make sense at all.
Remember, most paging files are very large, a few hundred megabytes to a gigabyte in size. Most computers even come with enough memory to create such a large RAM drive, much less move the entire paging file to the RAM drive.
Even if you have a lot of system memory, creating a large RAM drive reduces the pool of available system memory. This increases the need for virtual memory which means more data will have to be paged out into the paging file. This increases the size of the paging file which will inevitably be much larger than the RAM drive.
At this point, Windows will automatically create more virtual memory via a dynamic paging file. Because a large portion of the system memory has already been taken up by the RAM drive, this will cause a lot of data to be paged out to a large dynamic paging file on the hard disk. That defeats the purpose of moving the paging file to the RAM drive - improved performance.
If your system has a lot of system memory, don't waste your time creating a RAM drive to service the paging file. If there is a lot of free system memory, Windows will not need to page out data to the paging file. That would produce the best results. Nothing is faster than running the programs directly in system memory.
Reducing Reliance On Virtual Memory
Windows can get too enthusiastic about paging data out to the paging file. This can lead to unnecessary paging, even when there is a lot of free system memory.
Luckily, we can do something about this :-
+ Enabling the Pagefile_Call_Async_Manager service (Windows 98, Me)
+ Stop NTExecutive from paging (Windows NT, 2000, XP and above)
We will take a look at each and see how they work.
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