How do I enable the /3GB switch in Vista using EasyBCD?

[2Cold Scorpio]

Title says it all; I'm trying to set up a seperate boot option in the Vista bootloader that has /3GB turned on, which will leave my default boot option (standard Vista) untouched. I did this back in XP with ease (I miss boot.ini...) using two separate boot options (one that booted XP with /3GB and one without)and would like to replicate this functionality on my new Vista install. I only need /3GB for a handful of things, and don't want to mess with resetting it off or on all the time.

I've already cloned the Vista boot entry for my bootloader using EasyBCD; I just don't know how to go about setting /3GB on it for good. Does EasyBCD have this option? If not, how do I go about enabling it for that second boot option?

My bootloader currently looks like this:

-Windows Vista Ultimate <---this is the default one; don't want /3GB here
-Windows Vista Ultimate /3GB <---exactly the same as above (both booting from the same install), except I with to set this option to use /3GB

Any help would be appreciated.

[dangel]

I assume you can do it with BCDEDIT from a command prompt e.g.

"BCDEDIT /Set IncreaseUserVa 3072"

Would do it for the current boot entry, specify an identifier to set a specific one. Type BCDEDIT on it's own to see the current list.

Run this command from a command window with Administrator priviledge - i.e. (in the Start menu) type CMD and press Ctrl+Shift+Enter, or select "Command Prompt" (Accessories), right-click on it and choose "Run as Administrator".

[2Cold Scorpio]

Man, in XP it was a lot simpler...I had boot.ini set up with two entries, the second one having /3GB and /USERVA set, which was nice because I could use the top one day-to-day and have /3GB off, and the second option always had it on. That's the functionality I'm attempting to recreate.

[dangel]

Man, in XP it was a lot simpler...I had boot.ini set up with two entries, the second one having /3GB and /USERVA set, which was nice because I could use the top one day-to-day and have /3GB off, and the second option always had it on. That's the functionality I'm attempting to recreate.

Yup, I understand where you're coming from! I still think you can do it (as described) but even VistaBootPro doesn't have that option so you're a bit stuck (BTW I notice pro networks now charge for that).

[2Cold Scorpio]

You know, I see EasyBCD has an option under the Advanced Options that says:

"Deduct X MB from physical memory (leave at 0 to reset)"

I wonder if that would be it...

[dangel]

Sounds more like an option to reduce the total amount of memory available - that's different from what you're asking for:

The /3GB switch changes the way the 4GB virtual address space is split up. Instead of splitting it as 2GB of user mode virtual address space and 2GB of kernel mode virtual address space, the split is 3GB of user mode virtual address space and 1GB of kernel mode virtual address space.

That's all.

I suppose i'll ask the question, what are you trying to achieve? An app has to be aware to use the extra user mode space - it won't do it automatically.

[2Cold Scorpio]

I have one specific app that uses it (Cinematic Mod 9 for Half-life 2...it eats up RAM like no tomorrow); it was really means to run on 64-bit Windows, but I found it worked just about as well when I ran XP with the /3GB switch. Now since I've migrated over to Vista, I'm just trying to restore that functionality.

I've done some extra reading, and understand now that /3GB in Vista got replaced by UserVA (now I understand that bit above a lot more). UserVA also worked in XP; it was used to fine-tune /3GB. What I meant by reading the article and still saying it ought to work was the mechanics (you'll notice it says No Change next to XP as well, though /3GB did its job wonderfully there), though I didn't realize they had rolled up the two into being one command (which I do like; it simplifies things).

So I suppose my question changes to this: If I boot into the boot option I'd like to dedicate to using UserVA, and run "BCDEDIT /Set IncreaseUserVa 3072" in BCDEdit, will that change stick, or will I have to re-do it each time I reboot into that second boot option? Also, will it leave my first boot option without UserVA enabled?

What I'm hoping I can do is boot into the second entry, set UserVA, and have it stick there while leaving Option 1 untouched, pretty much like I did with XP.

[dangel]

AFAIK it should stick - you have to delete the variable with a seperate command to disable it again.
Do post up you results tho - someone else might find this interesting in the fullness of time.

[2Cold Scorpio]

AFAIK it should stick - you have to delete the variable with a seperate command to disable it again.
Do post up you results tho - someone else might find this interesting in the fullness of time.

Oh, I will. From what I've read, it seems you can get EditBCD to tell you whether its on or not, so that would tell me if having two different install options would actually make a difference (as in, hopefully it won't affect the first of the two; except for UserVA being active, there should be no difference at all between the two boot options--they both point to the same install of Vista). Either way, you've earned your Thanks; I stuck it to the post that contained the actual command.

Man, I wish I had a 64-bit OS at times like this... Cursed student copy of Vista Ultimate being restricted to 32-bit upgrade disks only! >.< lol Hurry up Windows 7!

[dangel]

Man, that sucks (the 32bit restriction) and is pretty short-sighted of MS IMHO!

Best of luck anyway m8! (and ta!)

[shaithis]

If you want to re-create the old XP functionality, then you need to get a handle on all the BCDEDIT switches.....there is a technet article that details the use of BCDEDIT.

Basically (from what I remember messing with it a while ago) you need to clone your current default config...

bcdedit /copy {current} /d "Vista with 3GB"

Take note of the SID that it creates the entry with, then I think you can do:

bcdedit /set {Your new entries SID} IncreaseUserVa 3072

Or something very similar...

[2Cold Scorpio]

If you want to re-create the old XP functionality, then you need to get a handle on all the BCDEDIT switches.....there is a technet article that details the use of BCDEDIT.

Basically (from what I remember messing with it a while ago) you need to clone your current default config...

bcdedit /copy {current} /d "Vista with 3GB"

Take note of the SID that it creates the entry with, then I think you can do:

bcdedit /set {Your new entries SID} IncreaseUserVa 3072

Or something very similar...

I think I already did the cloning part using EasyBCD: added a new entry, and had it point to the same partition. It shows up on the bootloader (I haven't booted into it yet, but i see no reason why it wouldn't work...

There are a total of 2 entries listed in the Vista Bootloader.
Bootloader Timeout: 10 seconds.
Default OS: Windows Vista Ultimate

Entry #1

Name:  Windows Vista Ultimate
BCD ID:  {current}
Drive:  C:\
Bootloader Path:  \Windows\system32\winload.exe
Windows Directory:  \Windows

Entry #2

Name:  Windows Vista /3GB
BCD ID:  {69e554aa-c2ee-11dd-90ef-854cb68caaf2}
Drive:  C:\
Bootloader Path:  \Windows\system32\winload.exe
Windows Directory:  \Windows

So I think that should suffice. I hope, anyways; it'd save me some work.

Edit: Off-topic, but this put me at 700 posts. Cool!

[2Cold Scorpio]

Well, I *think* this means its working...someone care to verify? If so, I'll post what I did so others can use it too if needed (like Dangel suggested):



If I'm looking at it correctly, the top boot option and the second one are exactly the same...except the second one uses the UserVA switch as well. Am I looking at this correctly?

[directhex]

Man, that sucks (the 32bit restriction) and is pretty short-sighted of MS IMHO!

Curse Microsoft for not defying the laws of mathematics!

[2Cold Scorpio]

Curse Microsoft for not defying the laws of mathematics!

Amen!...wait, haven't we cursed Microsoft for enough already?

[dangel]

Curse Microsoft for not defying the laws of mathematics!

Well, more curse them for not giving students the 64bit edition - read what he said

I can't see the sense in that - at all.