Virtual Memory

[Capricorn]

I am running XP Pro. When I shutdown I nearly always get the message that I am low on Virtual Memory, and that Windows is increasing it. What is the recommended setting for Virtual Memory?

[tha 4NiK8R]

I always recommend at least twice the amount of physical memory. Also don't make the pagefile differential (eg 512-1024) always make the min and the max the same size (eg 1024-1024). If you a have a differential pagefile you will fragment your harddrive faster than you can defrag it. Unless of course you are one of the people who don't believe in defragging or believe that NTFS does fragment: in these two cases you can set your pagefile to differential and just rebuild your machine every 6 months.

[Capricorn]

Thanks. It was different amounts, but I have done as you suggested and made both settings 1024. I am using NTFS.

[DANIMAL]

This will be long but worth reading. myth #1 may surprise you.Even thought this is for Win 98 I'm sure the points are the same in XP.

There are two possible advantages of a permanent Swap-File:
(1) A reserved contiguous, un-fragmented section of the HD.
(2) Eliminates disk activity from W9x re-sizing the Swap-File.

Be wary of some myths about the Swap-File passed on by well meaning folks nearly every time this subject comes up. I am surprise at how many seemingly knowledgeable people are perpetuating one or both of these myths in some of the popular PC Magazines, W9x help books and many websites.

Swap-File myth #1:
Create a permanent swapfile 2 1/2-3 times the amount of physical memory.

Fact: Virtual memory (Swap-File) is a substitute for physical memory. Common sense tells you the more physical memory you have, the less virtual memory you need. Conversely (all other things being equal) the less physical memory you have the more virtual memory you will need. There is no reasonable "rule of thumb" formula for setting the size of a permanent Swap-File.

Swap-File myth #2:
Set the 'min' and 'max' size the same for the Swap-File.

This one can cause you grief, it is bad advice!!! Some seem to think of the Swap-File like an insect trap, if you don't have a lid on it, all of those Ks and Ms of bytes and bits will fly out all over the HD. Not so!!! It may help to think of your Swap-File as a water glass sitting on the table (The level within this container will rise and fall as demands change and it is emptied whenever you shut W9x off), the only time it will overflow is if you try to put more into it than it can hold, (your 'min' size setting) and that is the reason you 'never' want to place a 'max' size for your Swap-File, you want it to overflow if it needs to. (This is an analogy, it will not overflow, the Swap-File will increase in size if need be, possibly using non contiguous HD space until it shrinks to your 'Min' size setting again.)

W9x will 'never' exceed your 'min' size unless it needs to, if it can't (because of a 'max' size setting) it will revolt, usually with a "Out of Memory!! Shut down one or more programs to continue" warning. It is doubtful you will associate this warning with the 'max' setting you placed on your Swap-File months ago when your usage habits were less demanding.

How to determine the optimum size for YOUR 'Permanent Swap-File'?

You can install System Monitor from the Windows 98 CD or simply download from here - System Monitor, click on the file you've downloaded called sysmon.exe, then open the extracted folder and click on sysmon.exe to start the System Monitor program. Then, click Edit, Add Item, Select Memory Manager, then Swapfile size and finally click OK.

Let System Monitor run in the background for a few hours or all day while you do your work, open multiple programs, browse the net, etc. Then at the end of day check to see the peak value of your swapfile. You can check the peak by clicking on the graph of the swapfile and looking at the bottom of the System Monitor which will show your peak value.

Here's the trickier part, the peak value is reported in kilobytes and we need to convert to megabyte. Take your peak value and divide by 1,024,000, and you'll have the peak value of your swapfile in megabytes. This will be the setting for your min value.

Where to put your 'Permanent Swap-File'?

I suggest placing it on your fastest HD, on the Partition with the most free space. If you have a motherboard that supports dual channel PCI-EIDE controllers, you may gain an advantage by placing the swap file on a second drive on the second channel as the your board may allow "Peer Concurrency" that allows for simultaneous access to two IDE drives on different channels.

Preparation for 'Permanent Swap-File' installation. Use the method that works best for you. The point is to have no Swap-File, or an empty Swap-File when you Defragment the drive you want your 'Permanent Swap-File' on.

(1) Open Control Panel/System Properties/Performance/Virtual Memory, click "Let me specify my own Virtual Memory settings". From the 'Hard Disk' selection window select any Drive Letter other than the one you want your 'Permanent Swap-File' on. Click "OK" then "YES" to the scary warning. Reboot your system to W9x. From START/FIND type in Win386.swp, search the drive you will want your 'Permanent Swap-File' on. If 'Win386.swp' is present, delete it.

(2) If you have >16M of memory this method will probably work for you. Be sure the 'min' setting for virtual memory is 'zero'. Make sure you do not have any programs that run at start-up, check with CTRL+ALT+DEL to be sure ('Systray' and 'Explorer' are usually all you need) reboot as many times as necessary to be sure Win386.swp is an empty file.

Reboot your system to W9x, from START/RUN type DEFRAG, select and defragment the drive you want your 'Permanent Swap-File' on.


An Even better way to defragment your hard drive is to use Power Defrag. You won't have to worry about the above or making sure any programs or screen savers are running in the background. Power Defrag does it all for you and makes backups and then restores any files that it changes. Power Defrag is NOT a third-party defragger, it uses the Windows built in defrag utility but optimizes the settings to give you the best possible defragmentation.

Download Power Defrag


Open Control Panel/System Properties/Performance/Virtual Memory, click "Let me specify my own Virtual Memory settings". From the 'Hard Disk' selection window select the Drive Letter you want your 'Permanent Swap-File' on. In the 'Minimum' window type in the size you have determined for your system (make NO changes in the 'Maximum' window). Click "OK" then "YES" to the scary warning, reboot your system.

If you check your 'Virtual Memory' settings you will notice that "Let Windows manage my virtual memory settings" is checked, this is normal. You will see that your 'Hard disk' selection and 'Minimum' settings show what you entered, 'Maximum' will show free space on HD or 'No Maximum' and all is grayed out, this is normal.

This next tip is for Windows98/98SE only:

To disable the "PageFile_Call_Async_Manager" feature that allows the Memory Manager to asynchronously write out swap file buffers during VFAT idle times. This reverts swap file usage back to Windows 95 style, and forces the use of the computer's physical memory (faster) first, before the use of the slower hard disk virtual memory (swap file) and reduces hard drive thrashing.

You'll need to edit your system.ini file by selecting Start, Run and type in system.ini. Once open scroll down to the section entitled [386Enh]. Create an open line below the title [386Enh] and type the following:

ConservativeSwapfileUsage=1

Now save the file and reboot your system.


Portions of this report have been reproduced from articles and FAQS in Microsoft newsgroups and Acel216's Windows Tip Site.

[DANIMAL]

<a href="http://www.wown.com/j_helmig/wxpvmem.htm" target="_blank">Just found this link here for XP machines.</a>

[korpse]

Microsoft recommends:
min - physical ram + 64
max - physical ram * 3

[Capricorn]

I've tried setting it to System Managed, I have tried the min and max the same size, I have tried min low and max high and still I get the message that Virtual Memory is low and Windows is increasing it at shutdown. could the fact that I am using the NTFS filing system be making any difference?

[Darren Wilson]

I haven't used a Swap File for ages now and never had 'Insufficient Memory' errors. Having large amounts of RAM does help though (I run 1Gb).

[Matridom]

Damnial is pretty pat on.

My rule of thumb goes has follows, run your computer non stop for several days (if posible) now open task manager and go to the performance tab. your interested in the "Commit Charge(k)" section.

Now the following is "general Idea" of what you want.

Total is the CURRENT total ram in use. This number should fit withing your "Total" of "Physical Memory(K)"

Limit is the MAXIMUM memory that the system has available (swapfile AND Phisycal) The number should be 1 1/2 times the size of "Peak"

Peak is the MAXIMUM amount of ram used at any giving point. This should NEVER exceed Limit.

so i follow this equation, (Peak * 1.5) - physical = swapfile Min

Here is an example of my system...(numbers are rounded)

Commit Charge(k)
Total 21700
Limit 76800
Peak 55100

Physical Memory(K)
Total 523000
Available 324000

Now my system has enough ram.. My Ram in use is well withing my physical ram. Also my peak is ALMOST withing my physical., my Limit is larger by a good factor of my peak, so I'm ok.

Under IDEAL conditions, Peak should remain WITHING Physical, if you can do that with a good safety margin( say atleast 200 megs) then Do as Daren does and turn off your swapfile.

[Darren Wilson]

I did run a thread here a few months back asking people to try running 2K/XP without a swap file if they had large amounts of RAM available. I have been checking the Memory usage by ALT+TAb'ng back to Task Manager with numerous programs running (including games, graphics packages, office apps,burning a CD etc all open at the same time) and at no point does the memory use go above 683Mb. One thing I haven;t tried (as I don;t own one :) ) is scanning a A4 image at the highest resolution. I would think that this may have an effect on the available memory.