I have a Dell XPS 410. I bought it with 2 GB of ram and added 2 more a week later. In setup, the BIOS reads all 4 Gb, but when I check in system information, it says I only have 3GB. Would the system even start if 1 stick was bad?

No your RAM is not dead, the 32bit version of Vista has trouble with reading more 3GB's of memory. I suggest that you read this article as it will explain things.

Hope that helps

Great article. Thanks for the help!

To enable all 4GB of your RAM on 32-bit versions of windows, you gotta do the following:

On your system drive, find a file called boot.ini. It's a hidden system file, so you gotta turn on those views. It's also read-only. Make sure you remove the read-only attribute.

On the line that has your operating system on it, underneath the [operating systems] header, add the following to the end of the line:

Do NOT change anything else on this line!!!

This will allow 32-bit versions of Windows to address the entire 4GB of RAM. Works for XP/2003 too. Not responsible if you hose your system; I've heard that Vista sometimes might not like this switch, but it's worth a shot...I haven;t read the entire Anandtech article, but it looks interesting...

I guess it doesn't much matter now anyway that this 7month old XPS system just cooked 3 sticks of ram on 1 startup!

Quote: Originally Posted by Joose To enable all 4GB of your RAM on 32-bit versions of windows, you gotta do the following: On your system drive, find a file called boot.ini. It's a hidden system file, so you gotta turn on those views. It's also read-only. Make sure you remove the read-only attribute. On the line that has your operating system on it, underneath the [operating systems] header, add the following to the end of the line: Code: /3GB Do NOT change anything else on this line!!! This will allow 32-bit versions of Windows to address the entire 4GB of RAM. Works for XP/2003 too. Not responsible if you hose your system; I've heard that Vista sometimes might not like this switch, but it's worth a shot...I haven;t read the entire Anandtech article, but it looks interesting...

I would like to see this article... From what I understand that will allow windows to "see" more then 3GB... but it is still bound to the physical address limitation of 32bit which will "not" use more than 2.7GB (that is all of the memory, system, video, ect... combined btw)

If you can find a credible article that proves me and everyone else that has read about this wrong I welcome it.....

Quote: Originally Posted by Twizted I would like to see this article... From what I understand that will allow windows to "see" more then 3GB... but it is still bound to the physical address limitation of 32bit which will "not" use more than 2.7GB (that is all of the memory, system, video, ect... combined btw) If you can find a credible article that proves me and everyone else that has read about this wrong I welcome it.....

Even though it says it only works on Server, that's not true; I've used it with XP. This explains it well:

How to Set the /3GB Startup Switch in Windows

And if the standard 1GB to System/3GB to applications makes your system unstable, you can tune how much you give by following this article:

How to use the /userva switch with the /3GB switch to tune the User-mode space to a value between 2 GB and 3 GB

or this one:

How to Set the /USERVA Startup Switch in Windows

Then there's these articles explaining just what it's actually doing:

The Old New Thing : The oft-misunderstood /3GB switch
The Old New Thing : Myth: The /3GB switch expands the user-mode address space of all programs

Standard procedure for servers with 4GB RAM running Windows Server 2003 Standard is to add the /3GB switch to them. The memory "seen" jumps from just over 3GB by default, to 4092MB.

I've done this many times in my environment of over 200 servers.




After all that, I forgot that the /3GB switch really isn't what you're looking for!!!

Forget my instructions above. In Vista it's going to make your system really unstable. Instead of using the /3GB switch in your boot.ini you have to enable the Physical Address Extensions in the exact same place. So instead of /3GB switch, please append this switch to the line just under your [DEFAULT] entry in boot.ini:

Here's a technet article explaining what it's doing:

Large memory support is available in Windows Server 2003 and in Windows 2000

Hope that helps, and I hope you're not thoroughly confusered.

OK Twiz...and injuneer1 (welcome to PCX by the way )

This is the definitive article:

Windows Vista or Windows Server 2003 may report less memory than you expect

Hate to say I told you so

Oh yeah...and if you're not dual-booting (I am) you'll need to follow the instructions in the article linked in this post to enable PAE for Vista. I didn't know that.

Well, If I had a machine here to test it on I would... I am not saying its wrong as you did come up with a lot of articles but I am still not sure if its just seeing it or using it to... hmmmm

Quote: Originally Posted by Twizted Well, If I had a machine here to test it on I would... I am not saying its wrong as you did come up with a lot of articles but I am still not sure if its just seeing it or using it to... hmmmm

I know where you're coming from; it's not that you're making more memory than you've already got, it's just reallocating that memory to make the operating system better aware of where the memory actually is.

Remember the limitation for 32-bit operating systems is 4GB. This is a hard line. What the PAE switch is doing is effectively enabling a 'driver' (for lack of a better word) to allow memory that is pushed just beyond the 4GB barrier by the motherboard/bios, to be 'seen' by the operating system. It doesn't happen to ALL systems, but is does happen in the majority of systems. When it does happen, you 'lose' quite a bit of RAM.

PAE isn't all it's cracked up to be though. If you compare a 32-bit PAE system that has 4096MB ram available to it to the exact same system running a 64-bit version, the 64-bit version will run faster, due to native addressing support. The PAE switch comes at a cost; there is a *little bit* of a performance hit. It's generally offset though by the extra RAM available to the system.

If you compare performance pre and post-PAE, you should see a performance boost, albeit small.

lol I know it cant make memory thats not there I am saying this goes against everything I have ever read about OS's and memory allocation and ability... I just talked to my bro here at the shop.. He said the "Hard line" is 3.2GB on a 32bit system for all memory in the system (video and all)

It just goes against everything I have ever learned and read... I guess this would have to be shown to me hands on to really get me on board with the idea... just to many years and articles saying otherwise I guess....

Quote: Originally Posted by Twizted lol I know it cant make memory thats not there I am saying this goes against everything I have ever read about OS's and memory allocation and ability... I just talked to my bro here at the shop.. He said the "Hard line" is 3.2GB on a 32bit system for all memory in the system (video and all) It just goes against everything I have ever learned and read... I guess this would have to be shown to me hands on to really get me on board with the idea... just to many years and articles saying otherwise I guess....

3.2GB is a 'soft line' if you will; Microsoft opsys's 2000+ can be enabled to allocate that extra 800MB RAM by using the PAE switch. It's a trick that sysadmins have been using for years on MS SQL servers and MS Exchange Servers...in fact, Microsoft actually recommends that you enable both /3GB and /PAE on Exchange servers with 4GB RAM in them for this very reason.