Re: The /3GB Switch..

JD wrote:

John John (MVP) wrote:

JD wrote:

Ian D wrote:

"JD" <JD@xxxxxxxxxxxxxxx> wrote in message news:eQ916bNiJHA.4868@xxxxxxxxxxxxxxxxxxxxxxx

I hate to mess with something when the computer is booting good and Photoshop is working OK. I'll take a closer look at the /userva switch but sometimes it's best to let sleeping dogs lie. If it ain't broke then I'll mess with it until it is?

I'm putting all your links into my Photoshop notes in case I want to experiment at a later date. Photoshop is just an expensive hobby for me.

I really do appreciate your help. I've learned a lot.


The /userva switch should be used if you're going to use
the /3GB switch. For 32 bit Windows the 4GB address
space is divided with 2GB allocated to applications and
2GB allocated to the OS. Applying the 3GB switch gives
the apps an additional GB at the expense of the OS.

The problem is that the OS's memory space is shared with
the hardware requirements, so if your hardware uses almost
all of the 4th GB, the OS is left with very little to work with.
This could result in excessive paging, or a crash. The
/userva= setting reallocates some space from apps back to
the OS. Adding this to the end of your boot.ini boot line
should be sufficient: /3GB /userva=2800. If you are
concerned about this setting, you could create a dual
boot with your normal XP, and XP with the /3GB for when
you want to use PS.

As a matter of interest, 32 bit Vista only uses the /userva
setting, as the /3GB is implied.


At this point, I don't use PS that much and when I do it's working OK so I'm not going to change anything. I'm keeping notes in case I decide to experiment later but that always seems to get me into trouble! ;-)

Since you mentioned it, how do I create a dual boot to use two different boot.ini files?


There not going to use two different boot.ini files, they will use the same file but the file will have different entries for the options you want. Post your boot.ini file here and someone will show you how to change it. Basically it would typically read like so:

[boot loader]
timeout=15
default=multi(0)disk(0)rdisk(0)partition(1)\WINDOWS
[operating systems]
multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Microsoft Windows XP"
/noexecute=optin /fastdetect
multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Microsoft Windows XP 3GB"
/noexecute=optin /fastdetect /3GB

John


What I'd like to try is the /3GB /userva=2800 switches. Let me see if I can get it right:

Current boot.ini:

[boot loader]
timeout=30
default=multi(0)disk(0)rdisk(0)partition(1)\WINDOWS
[operating systems]
multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Microsoft Windows XP Home
Edition" /noexecute=optin /fastdetect /usepmtimer

Switched boot.ini:

[boot loader]
timeout=30
default=multi(0)disk(0)rdisk(0)partition(1)\WINDOWS
[operating systems]
multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Microsoft Windows XP Home
Edition" /noexecute=optin /fastdetect /usepmtimer
multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Microsoft Windows XP Home
Edition" /noexecute=optin /fastdetect /usepmtimer /3GB /userva=2800

Did I get it correct?

Yes, that looks fine.


Now, can you tell me what happens when I boot? Will I be presented with some kind of option screen?

You will see two different boot options on a black screen and you will be able to use the Up/Down Arrows to select the boot option that you want. The text between the quotation marks in the boot.ini file is descriptive text for human eyes only, you can put whatever you want for the descriptive text and it won't matter to Windows XP and how it boots. Both of your entries will show on the boot menu as:

Microsoft Windows XP Home Edition

to make it easier to differentiate the different entries you could change the descriptive text for the /3GB entry to something like:

"Microsoft Windows XP /3GB"

If you wait more than 30 seconds (as set in the timeout=30 value) the computer will boot to the default multi(0)disk(0)rdisk(0)partition(1)\WINDOWS operating system, although in your case both options point to the same operating system, the ARC paths are identical, only the switches are different. I believe it would boot to the first option but I'm not 100% sure, you will have to try it and see.

Once Windows is booted if you want to know if the /3GB switch is used you can verify the SystemStartOptions value at:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control

John

.

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