April 14th, 2008
Although it is preferred to run software in physical memory, programs such as SolidWorks will need more space. In such events, Windows resorts to using virtual memory. Virtual memory is a paging file that resides on a harddrive to expand the memory used by a program beyond the actual physical limits of the physical memory plugged into the motherboard. This allows programs to work with files that extend in size over what is physically available on the computer.Â
Just as one may want as much physical memory available for SolidWorks as possible, one may also want to give SolidWorks access to as much virtual memory as possible. Additionally, increasing the size of virtual memory may improve computer performance to some degree. There’s a second trick that may help improve performance of the virtual memory in addition to increasing its size. If more than one harddrive is present on the computer, make sure to place the paging file for the virtual memory on the harddrive that is less frequently accessed and that is not used as a paging file location for other software (such as some Corel applications).
Here are the steps to change virtual memory size and locations (as with any changes to your computer, research your changes prior to making them; and any changes to your computer’s settings are taken solely at your own risk):
1. Open Windows Start menu
2. Select Control Panel
3. Select System
4. Goto the Advanced tab
5. Select the Settings button under Performance
6. Goto the Advanced tab
7. Select the Change button under Virtual memory
8. Choose the drive where you have or would like to have your virtual memory (in the Drive/Paging File Size field)
9. Enter the preferred minimum and maximum size of your Page File. It is recommended by some sources to make sure minimum and maximum values are set at the same value.
10. If you wish to move your Paging File, select No paging file and Set. Then highlight the drive where you would like your paging file to be, then go back to step 9.
11. Then OK, then OK again, and then OK again.
12. You should get a warning at some point about needing to reboot you system. Final step is to restart your system.
Categories: How-To, Tip/Trick |
Tags: physical memory, SolidWorks performance, virtual memory, windows performance | 4 Comments
April 9th, 2008
 *New additional details about boot.ini have been added at the end of this article in this color*
Windows NT, 2000, XP for 32-bit have one important limitation in memory management. By default, they limit any program running to 2GB of physical memory.  This means that if you have 3 or 4 GB of memory plugged into your computer’s motherboard, SolidWorks will still only use 2GB. To allow SolidWorks (and any other program) access to another GB of memory, employ what is known as the /3GB Switch. This is done by a modification to the Windows boot.ini file. Â
Using the /3GB Switch means that your software program uses more physical memory before it is forced to use harddrive space (virtual memory). The advantage is that physical memory is much faster than virtual memory, so SolidWorks performance should improved on larger files that might otherwise need to dip into virtual memory.
It should be noted that there are potential issues with using the /3GB Switch. Please see the hyperlinked article and Microsoft online resources if problems are experienced. Also, if you do choose to make this modification to your computer system, you do so at your own risk!
Here are the instructions to employ the /3GB Switch:
1. Open Notepad.
2. Goto pulldown File>Open.  Type C:\boot.ini into the file name area and select Open. The boot.ini file might be hidden from view, even if you have Windows Explorer set to view hidden files.
3. Save a backup of the file to something similar to C:\boot.bak.txt. This is so you will have a backup of your current settings if you need to quickly switch back.Â
4. Re-open C:\boot.ini.
4. Look for the something similar to following line within the file:
multi(0)disk(0)rdisk(0)partition(1)\WINDOWS=”Microsoft Windows XP Professional” /noexecute=optin /fastdetect5. Add a space character and /3GB to the end of that line. Do not make any other modifications to any other lines within this file. If troubleshooting is necessary on this line at a later time, look up the article at the
hyperlinked article and Microsoft online resources/references .   6. Goto pulldown File>Save As…. Type ”C:\boot.ini” with quotation marks. The quotation marks are important because Notepad will otherwise add a .txt to the end of the file name.7. Close Notepad.8. Restart the computer. Upon restart, Windows will attempt to boot with the /3GB setting activated.Additional note about the /3GB Switch is that there is an urban legend of sorts regarding how Windows manages physical memory. Some have mistakenly stated that Windows limits all applications it runs to the same 2GB of memory. This is not true. By default, Windows simply limits any program to a size limit of 2GB of memory. Multiple programs can and will use more than 2GB total if they are open at the same time. The /3GB Switch simply allows individual programs to access 3GB instead of 2GB. Of course, this is were issues may arise since some programs (such as video card drivers) may try to make use of the same 1GB extra physical memory; this can cause a conflicts. See the
hyperlinked article and Microsoft online resources/references for more details if problems are experienced.
Additional info about boot.ini: If you find that Notepad will not let you save boot.ini because it is read-only, you need to change the boot.ini preoperties (using Windows Explorer) to uncheck the read only setting. If Windows Explorer does not allow you to see the boot.ini, goto pulldown Tools>Folder options>View tab. Choose “Show hidden files and folders”. Uncheck “Hide extentions for known file types”. Uncheck “Hide protected operating system files”. Choose to apply to all folders and accept the changes. This will allow Windows Explorer to see the boot.ini. At that point, right click on the boot.ini and uncheck “Read Only” and accept changes. You will now be able to edit and save the boot.ini file with Notepad.
Categories: How-To, Tip/Trick |
Tags: /3GB Switch, boot.ini, SolidWorks performance, windows performance | 7 Comments
