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View Full Version : Help with the /3GB switch........



dmack
01-18-2008, 11:51 AM
Hi All,

I'm working on a project (hope to share some pics with you folk soon!) that has made my system run out of memory. So I added the /3Gb switch into the boot.ini - COOL! The scene that wouldn't render now does without issue.......except it seems nothing in life is completely free. I'm now getting regular 'insufficient system resources' error messages when I try and save the scene or save pfx files etc - Argh! So, I'm just wondering if this is normal with the /3GB switch or whether any techies out there might know a way of getting around this? My system has 4Gb of ram and I'm runnnig Windows XP. Any help really appreciated.

I'm going to go over to 64bit in the future but hey - the cash isn't there at the mo.

Titus
01-18-2008, 12:21 PM
I'n not a technical guy so not much advise from my part. I understand Vista can manage more than 3 GB.

lunarcamel
01-18-2008, 12:49 PM
I don't think XP or Vista (32 bit) can handle more than 3 GB of Ram. You may have it installed but it won't actually make use of it.

dmack
01-18-2008, 03:24 PM
The /3GB switch does allow applications to access greater than 2GB. I think it hands 3gb over to the applications leaving 1gb for the OS.

Anyone techie?

Lightwolf
01-18-2008, 04:18 PM
From the horses mouth:

The /3GB switch allocates 3 GB of virtual address space to an application that uses IMAGE_FILE_LARGE_ADDRESS_AWARE in the process header. This switch allows applications to address 1 GB of additional virtual address space above 2 GB.
XP32 sees the full 4GB. However, by default applications can only use 2GB of that. On top of that some of the 4GB are used to make i/o visible within the adress space of the OS (i.e. graphics frame buffer) - this eats away from the max. of 4GB (usually boards populated with 4GB can make 3.2 - 3.5 GB available to the OS).

It does make sense to use it if the machine has more than 2GB installed. And I've never seen more erros pop up because of that, sorry dmack, but I can't help you there.

Cheers,
Mike

P.S. LW is IMAGE_FILE_LARGE_ADDRESS_AWARE

IMI
01-18-2008, 04:25 PM
P.S. LW is IMAGE_FILE_LARGE_ADDRESS_AWARE


What does this mean in English? ;)

Lightwolf
01-18-2008, 04:34 PM
What does this mean in English? ;)
Requote: :D

The /3GB switch allocates 3 GB of virtual address space to an application that uses IMAGE_FILE_LARGE_ADDRESS_AWARE in the process header.
LW can use more than 2GB if the /3GB switch is used.

Cheers,
Mike

IMI
01-18-2008, 04:40 PM
Thanks. But I meant I was wondering what "IMAGE_FILE_LARGE_ADDRESS_AWARE" meant. That's OK though, I'll just Google it. :)

EDIT: The problem is the word "address". I see what it's about now though.

CreatvGnius
01-18-2008, 04:56 PM
It does make sense to use it if the machine has more than 2GB installed. And I've never seen more erros pop up because of that, sorry dmack, but I can't help you there. Cheers,
Mike

Mmm -wwwell, I don't know about that. Contrariwise, NewTek's SpeedEDIT™ installation disk has some suggestions in one of the docs, for getting faster performance with SE, from an XP machine, even if it had only 2GB of physical RAM.

The 3/GB switch enables the Win XP application that can take advantage of it -- to access more RAM (real and/or virtual) than it otherwise could.

Now that's if I understood correctly what I read just a couple nights ago. (Can't find that now that I'm looking for it. Also didn't find it in the FAQ area at NewTek's site either. (It *couldn't* have been a dream...) :sleeping:
-PeterG

Lightwolf
01-18-2008, 06:40 PM
Thanks. But I meant I was wondering what "IMAGE_FILE_LARGE_ADDRESS_AWARE" meant. That's OK though, I'll just Google it. :)
Basically a flag that you set when compiling the executable. This is used to tell the OS that it is safe to let the app allocate more than 2GB.
I presume it was introduced because early apps used some dirty tricks. If the app can only use 2GB, you only need 31 out of the 32bits to store an adress to a place in memory. The remaining single bit can be mis-used for other things (bad practice, but that happens in the real world). Another posibility is (again, mis-using) storing the memory location in a 32bit integer (scalar in LW nodal speak). If it is a value that is signed (can be negative or positive) then the last bit defines the sign. You don't want that when accessing memory though, which starts at 0 and progresses from there.

Cheers,
Mike

Hopper
01-18-2008, 06:45 PM
...and as a side note, you can install Windows 2003 server, disable all the crap that loads up by default and use a full 8GB of RAM. With very few registry edits, you can turn Windows Server into XP.

Now ... I'm sure you have paid your $4k license for that too. :thumbsdow

Hopper
01-18-2008, 06:51 PM
If it is a value that is signed (can be negative or positive) then the last bit defines the sign. You don't want that when accessing memory though, which starts at 0 and progresses from there.
So if you flip the bit, does it take all your memory away? :D

It is also a great way to force a GPF. And if you're working with a device driver, it's a great BSOD easter egg! We re-wrote a generic mouse driver to force the 32nd bit whenever the location reached the max X and Y resolution mark. Man is that funny when people get sloppy while mousing over a down scroll bar.

And yes... we were bored out of our skulls. Geeks do things like that.

IMI
01-18-2008, 09:00 PM
Basically a flag that you set when compiling the executable. This is used to tell the OS that it is safe to let the app allocate more than 2GB.
I presume it was introduced because early apps used some dirty tricks. If the app can only use 2GB, you only need 31 out of the 32bits to store an adress to a place in memory. The remaining single bit can be mis-used for other things (bad practice, but that happens in the real world). Another posibility is (again, mis-using) storing the memory location in a 32bit integer (scalar in LW nodal speak). If it is a value that is signed (can be negative or positive) then the last bit defines the sign. You don't want that when accessing memory though, which starts at 0 and progresses from there.

Cheers,
Mike

Cool. Thank you. :)

dmack
01-19-2008, 04:13 AM
This is a real bummer. The /3GB switch has definitely helped the scene render (I can have three lancasters instead of one!) BUT having issues saving (inc the scene) just doesn't sit comfortably with me. How can I see what processes are loaded on startup and are there any ones that really aren't needed?

Lightwolf
01-19-2008, 04:25 AM
How can I see what processes are loaded on startup and are there any ones that really aren't needed?
That shouldn't really matter, unless you use third party services. Turning off un-needed services doesn't really help that much.
However, you should check your drivers and get the latest versions. They tend to be the biggest culprits of problems running with the /3GB switch.

Cheers,
Mike

dmack
01-19-2008, 10:32 AM
That shouldn't really matter, unless you use third party services. Turning off un-needed services doesn't really help that much.
However, you should check your drivers and get the latest versions. They tend to be the biggest culprits of problems running with the /3GB switch.

Cheers,
Mike

Thanks Mike - What drivers might need changing - graphics card? Anything else?

Lightwolf
01-19-2008, 04:37 PM
Thanks Mike - What drivers might need changing - graphics card? Anything else?
Probably not the gfx card, they seem to have been stable for years. PRobably the more obscure stuff, audio, networking, especially if it is a smaller brand.
I.e. you can expect intel, AMD or nVidia drivers to be compatible.

Cheers,
Mike

KevinL
01-19-2008, 07:33 PM
dmack, I have used the 3G switch for years with both After Effects and Lightwave and never had any problems. Possible thought, there is some conflict in your setup that did not come to light until the 3G switch allowed something to get shuffled into a different memory space that now causes problems.

Good Luck,
Kevin

dmack
01-20-2008, 09:15 AM
Thanks guys. OK so the PC is from DELL adn I've only added a DVD burner - nothing I'd expect to cause problems? I've only had the /3gb switch on recently so it's difficult to say where I'm having problems but so far it has only been within LW....next time it happens, I'll switch over to explorer and see if there are any issues copying files around or creating text files.

I'm guessing it's time to go over to a 64bit os (I'm thinking XP64 rather than Vista).

If you have any other thought - do let me know - it's such a shame to have this otherwise excellent solution (/3gb) tarnished.