USERVA Switch
From ProPHOTO WIKI
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This article covers an advanced topic and improper usage of these settings may cause adverse effects. Please carefully read the entire contents of this article before implementing any changes. |
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Introduction
This switch allows users to fine tune the ammount of virtual memory space allocated to individual programs running Windows. When the /3GB Switch is activated, its default configuration is to assign 3GB of address space to the program and 1GB of address space to the kernel. In many cases, this will not provide sufficient room for some device drivers and can cause significant stability issues with the computer. This switch allows the user to set the user space to any arbitrary value between two and three gigabytes.
Note - This switch only works in combonation with the /3GB Switch. For the /USERVA switch to have any effect, the /3GB Switch must also be set in the boot.ini file. As such, please read through the /3GB article and make sure that you understand the manner in which this system works.
Warning - As noted above, this is an advanced setting and should be used with caution. Please read the entirety of this article and the /3GB Switch article before proceeding with the following steps. If you have any questions, please don't hesitate to ask.
Windows Vista
Due to a different boot process, users of the Windows Vista platform must use the IncreaseUserVa mechanism to enable this functionality. The method described in this article is only for the older platforms listed in the /3GB compatibility section. Vista users should see this article for more information.
Using the Switch
After finding that the /3GB Switch produces an unstable system, the /USERVA switch can be used to fine tune the allocation of memory. To use this switch, perform the following steps (please note, these instructions assume that you've performed the steps described in this article):
- As the computer restarts, but before Windows launches press the F8 key to get the boot menu (Windows may do this automatically for you).
- Highlight the 'Safe Mode' entry with the up and down arrows and press enter to begin booting.
- Windows will now boot into safe mode, with the /3GB Switch temporarilly disabled.
- Open Notepad (Start->Programs->Accessories->Notepad) and open "C:\boot.ini" (it may be hidden, so simply type that path into the file name field and hit enter).
- Make sure that the /3GB is still present as described here.
- Add /Userva=2900 to the end of the line and save the file.
- Close notepad and reboot the computer.
If the computer reboots and works as expected, then you are finished and can use the computer as desired. If it still refuses to boot and/or is experiencing stability issues, repeat the above process but reduce the number specified in step six above by 64. Continue this process until you locate a value that allows the system to operate properly.
Note - If the machine is booting properly, but experiencing other issues you can skip steps 1-3 above. They are simply required if the machine fails to boot with the /3GB Switch active.
See Also
- /3GB Switch - Allows the use of non-standard allocations of virtual memory space. This switch provides the ability to fine tune that behaviour.
- IncreaseUserVa - Mechanism used by Windows Vista to control this functionality.
- Virtual Memory - The mechanism that is used by modern systems to dynamically manage memory. This switch controls several facets in the operation of this system.
