First of, the more RAM you have the better, 128MB RAM is ideally the minimum of what anyone running Windows 2000 should have. This OS, much unlike Windows 9x has far better Memory management, one reason for this is because its meant to, Windows 2000 is intended for business/server use, not as a desktop system. Windows 2000 also uses a Paging file, which for all intents & purposes is the exact same as swap file in Windows 9x, just a different name (pagefile.sys) & a few other subtle differences.

If you have below 128MB RAM or less then you really should buy more RAM. This would be of far greater benefit to you than anything else. Much like the Windows 2000 Services guide this one goes into detail regarding settings & such, although if you're like me it's nice to know why & what you are doing. This is also probably the most comprehensive/definitive Windows 2000 memory guide around in terms of topics, settings & definitions covered. With that, on with the guide.

IMPORTANT NOTE – You must be logged in as an Administrator to make (most) changes to these settings. So log on as one if you haven't already done so.

What is Virtual memory?

It is a hidden file on the hard disk that Windows 2000 uses to hold parts of programs & data files that do not fit in memory. The paging file & physical memory, or RAM, comprise virtual memory. Windows 2000 moves data from the paging file to memory as needed & moves data from memory to the paging file to make room for new data. Paging file is also called a swap file.

Another explanation is that it is, temporary storage used by a computer to run programs that need more memory than it has. For example, programs could have access to 4 gigabytes of virtual memory on a computer's hard drive, even if the computer has only 32 megabytes of RAM. The program data that does not currently fit in the computer's memory is saved into paging files.

However, it is generally more efficient to set this yourself rather than let Windows 2000 manage it (Although Windows 2000 does much better Memory management than Windows 9x does).

Hard drive setup

As you may know, the Page file exists on your hard drive(s), which is much slower than using RAM. So speeding up your hard drive can improve Page file performance a lot. Although more RAM is highly recommended, having fast hard drive will suffice.

Open My Computer, right click on the hard drive(s), select Properties. Select the Hardware tab. Now highlight the desired hard drive & click the Properties button. Finally, select the Disk Properties tab & SCSI Properties, where applicable. The following options can improve Hard drive performance. NOTE - Some of those options may, or may not be available depending on hard drive type, e.g. SCSI or IDE.

Write cache enabled: If you enable this feature, your computer sends an enable-write-cache command to the hard disk activating the hard disk write-back cache, & if you disable this feature, the hard disk write-back cache is deactivated. When enabled disk I/O performance may improve, although if you experience system failure e.g. Power loss, you could experience drive/file corruption. I'd recommend leaving this ticked unless your system is prone to bad shutdowns/power failure.

Disable Tagged Queuing: Tagged queuing is done by the SCSI controller & driver to increase the speed of completing I/O tasks. This is accomplished by sorting the commands so the order of the commands issued to the physical disk drive to read or write results in the most efficient movement of the physical read & write heads. As you can guess, doing it in this sequential order is far more efficient than when disabled, resulting in greater I/O performance. You should only tick this if you are experiencing problems with a hard drive(s) as performance is slower when Tagged queuing is Disabled. Leave it unticked.

Hard drive setup (Cont.)

Disable Synchronous Transfers: There are 2 methods of transferring data over SCSI cables, Synchronous & Asynchronous mode. Asynchronous mode transfers use an interlocked handshake method where a device (adapter or drive) cannot do the next data transfer operation until it receives positive acknowledgment that the other device received the last data transfer properly. Synchronous transfer mode permits the sending device to send multiple data packets without receiving acknowledgment that the receiver actually received every data packet sent. As a result, more data can be sent/received before acknowledgement is required. You should only tick this if you are experiencing problems with a hard drive(s), e.g. overlapped requests, as performance is slower when Synchronous Transfers is Disabled. Leave it unticked.

Enable DMA support on your drives. Right click on My Computer, select Properties. Select the Hardware tab, then the Device Manager button. Open IDE ATA/ATAPI controllers, then open Primary & Secondary IDE Channel. Select the Advanced settings tab.

Enable ATA/UDMA 66 support, assuming your hard drive(s) supports it that is. By default in Windows 2000, support for ATA/UDMA66 is disabled (On Intel chipsets at least). Click on Start, Run, type in regedit & hit Enter. Go to [HKEY_LOCAL_MACHINE\System\CurrentControlSet\
Control\Class\{4D36E96A-E325-11CE-BFC1-08002BE10318}
\0000]. Add a New DWORD value entitled EnableUDMA66 & give it a value of 1 to enable support for UDMA/ATA 66, 0 disables it. This can greatly improve hard drive performance if supported, remember the Page file is located on your hard drive(s) too; the faster the data transfers the faster your Page File is. NOTE – This is not the same as enabling DMA support as shown previously.

Memory dumps

Windows 2000, much like previous versions of NT, will dump the contents of memory to Memory.dmp in the event of a Stop, or other fatal error. You can then use this Memory.dmp file for debugging the cause of this error. If this is your sort of thing you'll need to have your Paging File set to (at least) RAM + 12MB for the file to be created.

Personally, I don't find this of much use to myself, nor should it be of much use to most users out there. To edit the Memory dump settings, right click on My Computer, select the Advanced tab, then the Startup and Recovery button. You should concern yourself with the settings under the Write Debugging Information heading.

I'd personally recommend setting it to (none) unless you are into debugging crashes. Ask you System/Network Administrator for more information if possible.

Why concern yourself with this? Well, if you have your machine setup to write these Memory dumps you need a certain amount of Page File in order to do so, hence it effectively limits what you can do with your Page File settings. If you select Complete Memory Dump then follow the recommended Minimum of RAM + 12MB for the Page File, or use RAM * 1.5. You should also skip the Calculating Paging File size section.

Dual/Multiple CPU’s

As you probably already know (or are about to) Windows 2000 supports multiple processors. What affect does this have on the Page File? Quite a lot actually - Multiple CPU’s means multiple (more) L1 & L2 cache. L1/2 cache is significantly faster than RAM & the Page File is, as a result having more of this will mean less Page File usage.

If you upgrade your current system to one that has multiple CPU’s then you’ll need to take the following procedure as you’ll need to update the HAL (Hardware Abstraction Layer) to be able to support these extra CPU(s).

Before doing so check whether or not your manufacturer offers a specific HAL update for this purpose. NOTE – Some of the following information can be read in this MSKB article.

1.       Right click on My Computer, select Properties.

2.       Click the Hardware tab, then click the Device Manager button.

3.       Open Computer & then double click on the computer type that is listed there, e.g. on my system that would be Advanced Configuration and Power Interface (ACPI) PC.

4.       Select the Driver tab, then the Update Driver button. Finally, click the Next button.

5.       Select Display a list of known drivers for this device, then select the Show all hardware of this device class button.

6.       Select the Manufacturer & Model as appropriate (one that matches your current type, except for multiple CPUs), click Next, and then click Finish.

Calculating Page File size

Before you can set your Page File you’ll want to get an idea of what to actually set it too. Some recommend using a general formula, e.g. RAM*2.5. This is incorrect however. Using that formula, a person with 16MB RAM should set 40MB, while a person with 128MB RAM should set 320MB. Clearly the person with little RAM needs a greater amount of Virtual memory than the person with a lot of RAM.

To begin with, let Windows 2000 manage your Virtual memory settings, although with 1 adjustment. During Installation Windows 2000 by default sets your Paging File to Physical RAM*1.5. The adjustment is to simply set the Maximum = Minimum/Initial size. To change this right click on My Computer, select Advanced then the Performance options button, then Change. Simply edit the Maximum size to equal the Initial size & then select Set & Ok. Reboot for the changes to take effect.

Open up System monitor (Click on Start, Programs, Administrative tools, Performance), open the Performance logs & alerts section, then Counter logs. In the right hand pane right click & select New log settings.

In the General tab select Add. For the Performance object, select Paging File. Select % Usage Peak & _Total respectively. Over the next few days load up System monitor & let it track your Page file size. I'd recommend saving the log as a Text file, e.g. CSV format.

It would be best to start tracking your usage when you go to play a game or something that will put your PC under a bit of stress. Run a few timedemos or play Unreal tournament/Quake 3 against some bots. This will give you an idea of your Page File needs, however don’t go overboard with the testing you want to track normal usage, not excessive usage. The results are saved in the log file.

Once you’re satisfied with your monitoring its time to consult the logs. Open your memory.csv (or whatever you saved it as) with Notepad. You’ll be greeted with something like this.

E.g. In the logs shown above, 13.37 is the peak value. Assuming my Page File had been set to 192MB then my recommended value would be worked out as follows. 192/100 = 19.2, 19.2 * 13.17 = 25.6704MB, or 26MB.

Setting the Page file

Based on your results, there are 2 different methods that should be considered when setting the Page file. 1 is to create a permanent, fixed page file; the other is to create a semi-permanent one. The benefit of a semi-permanent one is that, if needed, Windows can enlarge the size of it accordingly. This will eliminate the chance of Out of memory errors occurring. After any resizing of the page file above the minimum Windows will bring it back to its original Initial size.

If you want to go the Permanent route then set the size about 30-50MB’s larger than the value you’ve calculated, e.g. given the values calculated above you’d set both the Minimum & Maximum to 70MB. This will allow for unforeseen circumstances where extra Virtual memory is needed. Given the large size of hard drives today you should have no problem allowing for the extra space needed for this.

Once you’ve decided on which method you want to choose, take the following steps.

1. Defragment your hard-drive & then reboot your PC.

2. Right click on My computer & select the Advanced tab.

3. Select the Performance options button.

4. Select Change. Select the hard drive(s) you wish to use for the Paging File. Chose step A or B depending on which path you choose to take.

5 A. If you’ve chosen to use a Permanent fixed page file set both the Initial size & Maximum size the same (substitute in your own values of course).

5 B. If you’ve chosen to use a Semi-Permanent page file set it as shown below (substituting in your own values of course). For the Maximum size however set it to double the minimum depending on the size & amount of free space (or use more/less if you see fit). The values shown below are those I use.

Remember, the Initial size is what will automatically be used for the Page File, no more will be used unless it’s needed, up to the Maximum Size.

Further optimizing the Page file & Memory

Below are some other tips to improve your page file performance &/or stability.

Try to avoid having a Page file on the same drive as the system files. This only applies to those with multiple hard drives available for use.

Avoid putting the Page File on a fault-tolerant drive, such as a mirrored or RAID5 volume. Page file(s) don't need fault-tolerance, & some fault-tolerant systems suffer from slow data writes because they write data to multiple locations.

Don't place the Page File on different partitions on the same disk drive. Placing the Page file on a separate partition increases access time & head movement. NOTE – This is not the same as placing it on separate hard drives. If you have multiple hard drives try either placing the Page file on the other hard drive, or split evenly between both hard drives, as shown below.

The Page File is best placed on the outer edge of a hard disk, where it can be accessed quickest. Windows 2000 Disk Defragmenter won’t do this unfortunately. You’ll need a disk defragmenter like Norton speed disk to do so.

It is not recommended that you put your Page File onto a separate partition as this will increase the time to access it & increase hard drive head movement as well. Instead, it is recommended that it be placed on the most used partition of the least used drive. This will mean the drive where Windows is installed for users with 1 hard drive. If you have another hard drive installed you should use that instead. To change where the Page file is located, change the Hard disk location when setting Virtual memory.

You can also optimize performance for memory/processor use, depending on how your PC is used. Go back into Performance options. You have a choice to optimize for either Applications or background services. Unless you are running something like a server you'll want to select Applications, this specifies that more processor resources are given to the foreground program than the background program. This helps out if you are playing games or other such programs. Servers will generally need to allocate resources evenly across all running tasks, so select Background services for these; this specifies that all programs receive equal amounts of processor resources.

Open a new text file up, using Notepad. Enter in the following line:

Mystring = Space(16000000)

Save it as filename.vbs, where filename is whatever you choose to name it. The .vbs extension is very important though, choose to save it as All files otherwise it will end up as filename.vbs.txt which won't work. You should close all running applications before using it. To use it simply double/single click it. Also, if you wish you may use values greater than 16. Don’t set it higher than the amount of RAM you have though.

Finally, check out the Windows 2000 Services guide, which can help you reduce the Memory usage of services.exe.

Sharing the Page File

If you are dual booting Windows 9x & Windows 2000 you may find it useful for both Os’es to use the same Page File. This is a good way of saving space on a hard drive. For sake of convenience, you should set the Initial/Minimum size of the Page File the same for both Operating Systems, the Maximum size is irrelevant for this purpose as it reverts to the Minimum size when possible.

Before you consider renaming your Page File you must meet one criterion. That being that you cannot share a Page File on a NTFS partition, Windows 9x doesn't recognise NTFS. As a result, you can only really share the Page File when on a FAT32 partition. For sake of convenience, I'll assume that you want to have both Operating systems share the Page File on the (FAT32) C:\ drive.

The Windows 2000 Page File is named pagefile.sys, while the Windows 9x Page File is named WIN386.SWP. You can rename either, although renaming the Windows 9x Page File is easier. First load Windows 2000 & set your Page File to the appropriate size & location, e.g. C:\pagefile.sys. Once you've made your changes reboot.

Now load Windows 9x & set your Page file to the same Minimum size as the Windows 2000 Page File. Click on Start, Run, type in system.ini & hit Enter. Under the [386Enh] heading the changes will be made.

Change the following lines as appropriate;

PagingDrive=x:\pagefile - Change x to the appropriate drive, obviously set this to the same drive as the Windows 2000 Page File. Change pagefile to the name of the Windows 2000 Page file, i.e. pagefile.sys (unless you renamed the Windows 2000 Page file, in which case, substitute in the appropriate file name).

E.g. If I were to share my Page File on the C:\ drive then I would have PagingDrive=C:\pagefile.sys entered in.

MinPagingFileSize=x – Where x represents the Minimum/Initial size of the Page File. The value for x is in bytes & as you may recall it must be set to the same size as the Windows 2000 Page File. E.g. If the Windows 2000 Page File was 192MB then you should enter in 198 * 1024 (remember, value to be entered is in bytes) = 202752.

Registry settings

In Windows 9x there were a few extra settings to improve memory performance by adding/editing some lines in the system.ini, e.g. ConservativeSwapfileUsage=1 would significantly reduce Virtual memory use. Windows 2000 has other settings available, although they are accessed via the registry rather than system.ini.

Click on Start, Run. Type in regedit & hit Enter. Go to [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management]. You may add/edit the following entries as you see fit for your system. Some of these settings were obtained via various MS Knowledge Base articles.

ClearPageFileAtShutdown. This is a security related setting. Using this DWORD value you can "clear" the contents of the Page File when shutting down the machine. Right click on the entry & select Modify. A value of 1 enables this feature, 0 disables this. I'd recommend leaving this set to 0 unless you are truly highly security conscious. Performance is not affected, although shutting down will take longer as a result.

DisablePagingExecutive. Using this DWORD value, you can prevent pageable drivers & system code in the Windows NT Executive from being paged out to disk. Although this decreases the response time in systems with extremely large amounts of physical memory (RAM), it is critical that there is enough RAM installed. If you have enough RAM (128MB+ ideally) in your system then you can benefit from disabling Paging the NT Executive to the hard drive, with insufficient RAM performance may be adversely affected, so you may want to try this setting both enabled & disabled to see which is better. Right click on the entry & select Modify. A value of 1 disables Paging the NT Executive to the hard drive (faster), 0 enables Paging the NT Executive to the hard drive (slower).

IoPageLockLimit. Using this DWORD value you can specify the limit of the number of bytes that can be locked for I/O operations. Right click on the entry & select Modify. Select the Decimal button & enter in the amount (in bytes, e.g. 1024 = 1MB) that you wish to use. When this value is 0, the system uses the default (512K). The maximum value is about the equivalent of physical memory minus pad, which is 7 MB for a small system & grows as the amount of memory grows. For a 64 MB system, pad is about 16 MB; for a 512 MB system, pad is about 64 MB. Using values larger than the default (0) may improve performance. Right click on the entry & select Modify. Select the Decimal button. Try using values ranging from 1024 to 16384, in steps of 512.

LargeSystemCache. Using this DWORD value you can specify that the system favour the system-cache working set rather than the processes working set.  This allows Windows 2000 to use RAM – 4MB for disk caching purposes. The 4MB free is used for faster launching of new applications. By default in Windows 2000 Professional this is disabled, although in the Server version it is enabled by default. Right click on the entry & select Modify. A value of 1 enables the LargeSystemCache, 0 disables it. If you have a lot of RAM enabling this will be of great benefit to performance.

Registry settings (Cont.)

PagedPoolSize. NOTE – This setting is included more for sake of completeness than anything else, although some of you may find it useful. Using this DWORD value you can specify the size of the Paged pool in bytes. This setting is related to the Maximum registry size in Virtual Memory. When this value is 0, the system uses the default size (32MB). In [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control] there is an entry entitled RegistrySizeLimit (Or Add a New DWORD value). This specifies the total amount of space that can be consumed by Registry data. The system ensures that the value for RegistrySizeLimit is at least 4MB & no greater than about 80% of the size of PagedPoolSize. Setting RegistrySizeLimit to 0xffffffff (Hexadecimal) sets the value to be as large as 80% of PagedPoolSize. You can allow for a bigger Registry by setting the initial PagedPoolSize, or you can set the value of RegistrySizeLimit. If you want a very large Registry, set both. However, for all but a few domain controllers, RegistrySizeLimit never needs to be changed. When you set a registry size limit, it limits both the page pool size & the amount of disk space that can be used by the registry. The default is 8MB (25% of the default PagedPoolSize).

PagingFiles. This BINARY value contains the settings that you have set in Virtual Memory. It is however useful in that you may change the name of the Page File with this entry. Still, if you are dual booting with Windows 9x it is infinitely easier to rename the Win9x swapfile, rather than the Windows 2000 one.

SecondLevelDataCache. Using this DWORD value you can specify the amount of L2 cache you have in your machine. SecondLevelDataCache records the size of the processor cache, also known as the secondary or L2 cache. If the value of this entry is 0, the system attempts to retrieve the L2 cache size from the Hardware Abstraction Layer (HAL) for the platform. If it fails, it uses a default L2 cache size of 256KB. If the value of this entry is not 0, it uses this value as the L2 cache size. Right click on the entry & select Modify. Select the Decimal button & enter in the amount (in KB's) of L2 cache you have in your system. This can be quite useful with some CPU's, e.g. Pentium 3's can have either 512 or 256KB of L2 cache, depending on the model you have. It's also useful in that no time need be wasted determining the amount of L2 in your system.

SystemPages. This DWORD value is irrelevant to most people who are reading this, although if you really want to know more about it check out this Microsoft KB article.

POSIX, OS/2 disabling

You could free up a small amount of memory by disabling support for these 2 subsystems. This is a highly important tweak as essentially no other methods work now. Why? Windows 2000 File Protection System recreates renamed/deleted system files. So while the method of renaming the Posix & Os/2 files may have worked in Windows NT4, it will not work in Windows 2000. If you need support for either of these, you can simply ignore the sections regarding to deleting that subsystem.

You may want to backup the registry before doing this, or at least export the affected registry keys.

Click on Start, Run, type in regedit & hit Enter. Go to [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\OS/2 Subsystem for NT] & Delete all subkeys. Now go to [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Environment] & Delete the Os2LibPath entry. Finally, go to [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\SubSystems] & Delete the Optional, Os2 & Posix entries.

Reboot your machine for the changes to take effect. NOTE – As mentioned earlier, Windows 2000 will recreate renamed system files so search for the files that were supposedly "renamed", there most likely exists the original file, plus the renamed one in your System directory. Delete the renamed versions.

Conclusion

You’ve now optimised your Virtual memory system. With a bit of luck you should notice less hard drive accessing & less Page file resizing. Make sure to check out the other guides for optimising other components of your system.

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