4GB RAM Shows 3GB in Windows

jayzinho · 01-26-2009, 03:37 PM

I have 4GB of RAM (2 x 2GB) installed, but Windows (XP Pro) shows 3GB. I heard that you can do something with the /3GB switch in boot.ini file to sort this, but does it actually allow the extra 1GB to be used in the same way as the other 3GB?

I've read about "virtual address space" and "kernel mode virtual address space" but I don't know what that means.

Dunno if it would help but I have 2 spare 1GB RAM chips, although I think Windows XP Pro can only support 4GB RAM max.

I think, after a little research, that the 1GB of RAM that isn't showing is used by stuff like the BIOS and possibly my graphics card, is this correct?

Can anyone shed any light on what I am experiencing, and whether or not I am able to realise all 4GB's of RAM for my machine?

Thanks in advance,

Jay.

ech0419 · 01-26-2009, 06:30 PM

Without thinking twice I can tell you that you are running windows xp 32bit. 32bit versions of any operating systems can only support 3-3.5 gb of Ram. From my knowledge only 64bit versions can utilize more then 3gb of RAM.

If you are running a 64 bit copy then more then likely your motherboard does not support more then 3gbs of ram.

Solutions - Pick one
1. Deal with the 3gbs showing
2. Switch it up with the 2gb stick & 1gb stick (if and only if they are the same FSB and/or brand/model) Then you can put the other 2 sticks in another computer.
3. Upgrade to Windows XP 64bit edition although I strongly suggest using Windows Vista 64bit which is what I run.

Quote:

I think, after a little research, that the 1GB of RAM that isn't showing is used by stuff like the BIOS and possibly my graphics card, is this correct?

Well this is halfway true. It all depends but your GPU can reserve a certain amount of Ram for graphics. It automatically allots a certain amount and you can change that + or -. Despite this it will still show all of your ram in windows.

I'm about 92.84518% sure that I'm 100% sure you are running a 32bit copy of windows.

jayzinho · 01-27-2009, 01:49 AM

Thanks for your reply, yep I am running 32bit version of Windows. It's not possible to change this at the moment, but I think a 64bit version supports 128GB RAM depending on motherboard.

OK, looks like I'll just have to deal with it. I have a Dell Optiplex 740, and I think the RAM will only fit in a couple of other Dell PC models, so I'll probably just sell the spare stuff.

Thanks for your help!

jayzinho · 01-27-2009, 06:54 AM

I have another query - I'm not sure if this is the correct forum for it but here goes....

I am running Microsoft Virtual PC on my machine as well. Is there any way to use the spare RAM that I have and allocate it to my virtual machine? My thinking is can you specify which slots your OS reads RAM from? So, for example I have 4 slots for RAM, could I put 2 x 2GB RAM chips in the first two slots and 2 x 1GB in the other two and for each OS (maybe in the BIOS setup) specify to only read RAM from the specified slots? Is this possible, or is there any other way to achieve the same thing, or shall I just accept it and give up?

Thanks in advance,

Jay.

ech0419 · 01-27-2009, 06:33 PM

Well I've never heard of dedicating memory slots directly from the bios or the motherboard itself. If you could/can I would not suggest doing so, you're computer would not be very stable.

Like I said earlier your best bet for running a virtual system is to use a 64bit system. Then you can utilize the additional ram and run the virtual system more effectively.

See what you can do in terms of a virtual system. You can try out windows 7 x64 beta (via microsoft.com) for free until about a month after it is officially released. If you like it you can purchase it once it comes out.

jayzinho · 01-29-2009, 05:34 AM

OK cool, that sounds like the best option. I think I have a 64bit version of Vista kicking around that I haven't ever used before so I might give that a go.

What is the Vista equivalent to XP Professional?

Thanks.

ech0419 · 01-29-2009, 07:52 PM

uhm I have no idea. They changed the whole scheme, it's all media based. Ultimate is the best and business and premium aren't bad. Home basic is the most affordable basic one. If you can shell out the money get ultimate some of the features are really nice but then again wait for windows7.

Like I said you can get a free beta copy of windows 7 x64 to try out and see if you like it. Windows 7 is essentially Vista but they took the crap out, made it more efficient, user friendly and more customizable. I like it, I'll probably buy a copy if microsoft gives discounts to those who had already purchased vista...

jayzinho · 01-30-2009, 01:12 AM

Ok, thanks for the help. I think I'll try Windows7 to see what it's like.

Thanks again!

01-26-2009, 03:37 PM	#1 (permalink)
jayzinho Registered User Join Date: Oct 2007 Posts: 84 OS: win xp sp2	4GB RAM Shows 3GB in Windows I have 4GB of RAM (2 x 2GB) installed, but Windows (XP Pro) shows 3GB. I heard that you can do something with the /3GB switch in boot.ini file to sort this, but does it actually allow the extra 1GB to be used in the same way as the other 3GB? I've read about "virtual address space" and "kernel mode virtual address space" but I don't know what that means. Dunno if it would help but I have 2 spare 1GB RAM chips, although I think Windows XP Pro can only support 4GB RAM max. I think, after a little research, that the 1GB of RAM that isn't showing is used by stuff like the BIOS and possibly my graphics card, is this correct? Can anyone shed any light on what I am experiencing, and whether or not I am able to realise all 4GB's of RAM for my machine? Thanks in advance, Jay.

01-27-2009, 01:49 AM	#3 (permalink)
jayzinho Registered User Join Date: Oct 2007 Posts: 84 OS: win xp sp2	Re: 4GB RAM Shows 3GB in Windows Thanks for your reply, yep I am running 32bit version of Windows. It's not possible to change this at the moment, but I think a 64bit version supports 128GB RAM depending on motherboard. OK, looks like I'll just have to deal with it. I have a Dell Optiplex 740, and I think the RAM will only fit in a couple of other Dell PC models, so I'll probably just sell the spare stuff. Thanks for your help!

01-27-2009, 06:54 AM	#4 (permalink)
jayzinho Registered User Join Date: Oct 2007 Posts: 84 OS: win xp sp2	Re: 4GB RAM Shows 3GB in Windows I have another query - I'm not sure if this is the correct forum for it but here goes.... I am running Microsoft Virtual PC on my machine as well. Is there any way to use the spare RAM that I have and allocate it to my virtual machine? My thinking is can you specify which slots your OS reads RAM from? So, for example I have 4 slots for RAM, could I put 2 x 2GB RAM chips in the first two slots and 2 x 1GB in the other two and for each OS (maybe in the BIOS setup) specify to only read RAM from the specified slots? Is this possible, or is there any other way to achieve the same thing, or shall I just accept it and give up? Thanks in advance, Jay.

01-27-2009, 06:33 PM	#5 (permalink)
ech0419 Registered User Join Date: Mar 2007 Location: North Eastern US Posts: 172 OS: XP pro ~ Vista Ultimate x64 & x32 ~ os x 10.4 ~ Ubuntu 7.10	Re: 4GB RAM Shows 3GB in Windows Well I've never heard of dedicating memory slots directly from the bios or the motherboard itself. If you could/can I would not suggest doing so, you're computer would not be very stable. Like I said earlier your best bet for running a virtual system is to use a 64bit system. Then you can utilize the additional ram and run the virtual system more effectively. See what you can do in terms of a virtual system. You can try out windows 7 x64 beta (via microsoft.com) for free until about a month after it is officially released. If you like it you can purchase it once it comes out.

01-29-2009, 05:34 AM	#6 (permalink)
jayzinho Registered User Join Date: Oct 2007 Posts: 84 OS: win xp sp2	Re: 4GB RAM Shows 3GB in Windows OK cool, that sounds like the best option. I think I have a 64bit version of Vista kicking around that I haven't ever used before so I might give that a go. What is the Vista equivalent to XP Professional? Thanks.

01-29-2009, 07:52 PM	#7 (permalink)
ech0419 Registered User Join Date: Mar 2007 Location: North Eastern US Posts: 172 OS: XP pro ~ Vista Ultimate x64 & x32 ~ os x 10.4 ~ Ubuntu 7.10	Re: 4GB RAM Shows 3GB in Windows uhm I have no idea. They changed the whole scheme, it's all media based. Ultimate is the best and business and premium aren't bad. Home basic is the most affordable basic one. If you can shell out the money get ultimate some of the features are really nice but then again wait for windows7. Like I said you can get a free beta copy of windows 7 x64 to try out and see if you like it. Windows 7 is essentially Vista but they took the crap out, made it more efficient, user friendly and more customizable. I like it, I'll probably buy a copy if microsoft gives discounts to those who had already purchased vista...

01-30-2009, 01:12 AM	#8 (permalink)
jayzinho Registered User Join Date: Oct 2007 Posts: 84 OS: win xp sp2	Re: 4GB RAM Shows 3GB in Windows Ok, thanks for the help. I think I'll try Windows7 to see what it's like. Thanks again!