What is the benefits of having pagefile.sys on different partition?

Just as the title asks, does having the pagefile.sys on a different partition really increase performance (>20%) and does XP bootup faster? Thanks and have a nice day.

 

Myth - "Moving the Paging File to a different partition on the same drive improves performance."

Reality - "Moving the Paging File (pagefile.sys) to a different partition on the same physical hard disk drive does not improve performance. Simply using a different partition on the same drive will result in lots more head-seeking activity, as the drive jumps between the Windows and paging file partitions. Even though moving the paging file in this case can have the positive effect of defragmenting it, the loss in I/O performance out weighs any gains. It is better to simply defragment the paging file using PageDefrag and keep maximum I/O performance by leaving the paging file where it is with a single drive setup. - Source

Notes - However you can enhance performance by putting the paging file on a different partition and on a different physical hard disk drive. That way, Windows can handle multiple I/O requests more quickly. When the paging file is on the boot partition, Windows must perform disk reading and writing requests on both the system folder and the paging file. When the paging file is moved to a different partition and a different physical hard disk drive, there is less competition between reading and writing requests."

JC

 

as netbrakr said, there's no advantage. usually when you read about moving to a different partition, it's meant a different physical disk as in on a desktop. since most notebooks only have 1 hard drive, the net gain is nil.

 

It is possible that you can get slight performance gains by moving the file to the beginning of the drive (meaning to the first partition), since this area has slightly better access times. However, this may be outweighed by the fact that the disk head now has to move between the pagefile on one end of the drive, and other data which may be at the other end.

So for practical purposes, I'd say it makes no difference. You may be able to measure some +- 1-2% , but it's not going to make a difference either way.

 

I see... I guess I can cross this off my list of increasing performance on my laptop. Thanks for the replies.

 

I have 2 gigs of ram and I turned off paging which resulted in much performance improvements.

 

And how did you test that?

having a pagefile doesn't degrade performance. The entire point in a pagefile is that it's only used as a backup when you run out of RAM. If you have enough RAM, the pagefile is never used, and so, it doesn't slow you down.
But if you do run out of RAM, your apps will crash if you don't have a pagefile.

 

I always open up multiple programs at the same time when I am at work and all these programs take some space in ram. When switching b/w these programs I noticed a slight delay in loading them when they were not used for sometime. I found that paging saves unused programs in memory and save it on the disk to free up memory for more programs, and when you need them it will load it back again from disk to memory. My 2 gigs is enough for my programs to load up in memory and stay there as long as I need them. Therefore I turned off paging and noticed when I switch b/w open programs it happens instantaneously now without any delay. I have a yahoo widget which tells me percentage of free space in my ram so thats how i know how much ram is free and when it starts reaching 90%, i close a few programs and I am good to go again. I have my paging turned off for about 2 months now and none of my apps ever crashed up till now.

 

Well, once almost all your RAM is in use (for example when you hit 90%, Windows starts preemptively pushing some unused data to the pagefile. That's generally done in the background, causing no noticeable performance drop in the short term. In the long term, it gives you stability (because it's able to push data to the pagefile when needed) and performance (because it's able to keep RAM free for when new allocations are required. If it didn't do that, it'd have to push tons of data to the pagefile in one go, which would cause much worse stalls, and because it's able to avoid fragmentation much easier.

So in short, you're not really achieving much by disabling the pagefile. You get rid of some rare, unnoticeable loads, and in return you lose long-term performance and stability (unless you're able to monitor your memory usage yourself and close programs when needed, which works fine *until* some program decides to allocate, say, 400MB all in one go, bringing you over 2GB and crashing 4 random applications)

So no, disabling the pagefile is a bad idea. Even when you have lots of RAM, and even when it's not typically in use.

 

The pagefile is basically always in use. Whenever you open a program, no matter how much RAM you have, the program "reserves" THE MOST memory it could ever need. This is a much higher number than you'll see in mem usage. The reasoning is to make sure there is no delay in running the program if it would need to page an additional amount. I have only 370mb of physical RAM in use, however, I have an almost identical amount of pagefile used.

It does nothing to speed or slow your computer to disable this. If you only use a couple programs in a session, your computer may lock up much less frequently without it. But if you use one more in that session, it may completely crash because of unavailable memory.

Virtual memory has no bearing on performance because programs don't actually use it. They use available physical memory, and "page" what they "might" need in the pagefile. If needed, this is shifted over to physical RAM, and that is where a slowdown might occur. However, without a pagefile physical RAM usage gets a MAJOR boost because it has to cover each program's reservation.

 

It's not quite "the most memory it'll ever need", because that amount isn't known in advance. The program typically reserves a big chunk of memory to begin with, and furthermore, Windows allocates bigger chunks. (Or more formally, it reserves bigger chunks, and allocates the needed amount from that chunk. If a program requests 200 byte, Windows might reserve 64k and set that aside for future usage by the program. But that means the entire reserved chunk is "used", in that it's unavailable to other programs. And furthermore, Windows itself works in the background to keep a certain amount of RAM free to avoid delays when more memory is suddenly required.

So yeah, having a pagefile helps makes much more efficient use of your RAM, simply because these unused chunks can be put in the pagefile, allowing faster, easier allocation of new memory.

The problem is that "performance" isn't so simple to measure. True, occasionally you'll experience a short stall when tabbing between applications if some data has to be retrieved from the pagefile. But that's not the only factor.
it also matters how long it takes to allocate memory (which is faster when there's plenty of free memory, and it's not too fragmented, both of which can become problems without a pagefile). These effects are much harder to measure, but that doesn't mean they're less important (they might affect your framerate in games, for example, simply because Windows has to waste more time trying to allocate memory when requested)

 

I have to agree with Jalf. It is best to have at least some page file. a good page file setting could be the same size as the amount of RAM installed, but not the same when over 2GB is installed. e.g. 512 RAM = 512PF and 2GB RAM = 1 GB PF. Soemthing like that. It is good to have a backup just in case.

 

Having the pf on a different physical disk on a different ide/sata controller woiuld be a benefit. But if your using two drives on one ide controller your still limited to one drivr per controller at a time. But scsi and sata are different. Im not sure how much performance youll get out of this, but I say its worth the try on a boring day.

 

If your main concern is that the pagefile has become fragmented and may be affecting performance, check out this info from O'Reilly:

http://www.windowsdevcenter.com/pub/a/windows/2004/11/23/defrag_pagefile.html

Fairly easy to do and uses the apps that come with Windows. If you have Diskkeeper, it does defrag the pagefile.sys file. From what I've read, having the pagefile on another partition or another drive doesn't provide any noticeable improvement, even on a heavily used computer.

 

No, I was just wondering about it as I read here and there that some people have separate partitions for their OS, PF, and Programs.