Quote - The maximum page file size is dependent on the amount of physcal RAM. On my Athlon64x2 4400 machine with 4 GB of physical RAM, the maximum page file size is more than 4 GB (haven't tried out what the max is, I just entered a "reasonable" 6 GB).

You can actually set your page file size to whatever you want in Windows as long as it is smaller or equal to the maximum that Windows allows and can handle. The problem is that Windows will only use a certain amount of it. When you manually set your swap file size you will see a recommendation that Windows makes as to what your swap file size should be, as well as a maximum size.

The accepted standard for swap file size is 1.5 x the amount of RAM you have in your machine. This is also what Windows bases its recommended size on.

Quote - Distributing the page file across multiple physical drives can help performance, because Windows will use the drive that is the least active when it wants to swap out some pages.

The problem with this is that it is not always that clear cut when put into practice for three reasons -

Firstly, regardless of whether you let Windows manage your swap file size or set it manually, there is the above maximum that still applies and there is nothing that can be done to extend this.
 
Let's say for example you have 4 hard drives. You have set up your swap file to extend across the second (D:), third (E:) and fourth drives (F:) as per the recommended configuration (this is strongly advised because any disk I/O on your Windows partition slows swap file access down so you want your swap file to be on other drives to give it the most throughput you can as well as allow Windows to load its own files as quickly as possible). Now, if you have a 3Gb swap file with 1Gb chunks on each drive, and your application is using 2 Gb of it, it's obvious that Windows cannot allocate the application's swap space to the drive that has the least activity bcause it is necessary to fill up more than each swap file chunk can handle. This means that you cannot say with any certainty that your application's data will always hit a particular drive which has some of your swap file space allocated to it.

What's also important is that if you have more than one application using the swap file Windows will employ a first in first out approach to filling the swap file. This means that part or all of the chunks of your swap space on your fastest or least used drive may already be used so the application you may want to use that space can't.

The second thing is that using the least busy hard drive's swap space is a great idea in theory but very hard to enforce in practice. Windows will make a best-effort to manage your swap space for you but will not always do so completely economically for a whole bunch of reasons, not the least of which is that the more time Windows consumes on managing the data being written to the swap file, the longer it takes to actually write the data.

The last problem is that your least utilised hard drive may not be your fastest. Windows doesn't make any changes or allowances in the way it stores data or utilises swap space based on the performance of your hard drives. If you have 2 fast SATA II drives with NCQ (Native Command Queuing) technology and an old 120Gb PATA ATA/100 drive and your swap file extends across all three drives, Windows will not make allowances for the fact that the 120Gb is probably 5 times slower than the two SATA II drives.

In my experience, the best possible way to enhance your swap file performance is to place it all on a small but very fast drive which is used for nothing else at all. Something like a fast 80Gb NCQ drive would work nicely. Secondly you want to make sure that your swap file is NEVER fragmented. Fragmentation will always occur if you let Windows dynamically manage your swap space for you. What you should do is, once you have installed your Operating System, set both your swap file minimum and maximum sizes to the same recommended 1.5 x your RAM size on a different drive to the default that Windows puts the swap file on when you installed it. This ensures that a new single contiguous file is written to the new swap file drive and the size will never change because minimum and maxiumum sizes are the same. Windows will not let you completely remove your swap file on your default Windows drive but it will make it very very small (16Mb if memory serves me well).

Please don't take offence svdl! I wasn't trying to shoot you down. I was just adding my 2c of knowledge to the equation. :biggrin: