Memory doesnt show up ??? help please

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Weaksauce
Joined
Aug 27, 2004
Messages
66
Hi

I had 2 gigs DDR2 of memory.. and i installed another 2GB DDR2 memory, total i have 4 gigs, but when i right click on my computer and go to system properties it only shows 2.87. In bios i see the 4gb memory properly installed.

I also updated my motherboard BIOS. I dont know why the memory is not showing up in system properties ....dont know what to do??

When i click on Start - Programs - Accessroies - System Tools and then System Information.... in there. it shows total physical memory 4.096.00MB...

Can you help me out guys... I have intel I925XVC motherboard.. and the rest system info in my signature below.. I would really appreciate your help.. Thanks in advance..
 
come on guys.. help me out... Any suggestion would be really helpful.. Thanks
 
You won't see 4GB because some gets reserved for things like AGP, PCI, etc., but you should be getting at least 3GB or more....can you update your BIOS and chipset drivers?
 
I am having the same problem with my abit av8 mb. It claims to support 4gb memory and on bootup it shows 4gb but in windows mycomputer properties it only shows 3.00 GB of RAM??? and i have 4x1GB PQI dims. No idea why windows can't see more then 3gb of memory. btw it's windows xp sp2.

any ideas?
 
Yeah, what I said above.


What is your video card, and how much RAM does it have? Also, what is the size of your AGP Aperture set to in your BIOS?


All this stuff gets mapped into main memory. So does PCI addressing, among others.
 
sm8000 said:
Yeah, what I said above.


What is your video card, and how much RAM does it have? Also, what is the size of your AGP Aperture set to in your BIOS?


All this stuff gets mapped into main memory. So does PCI addressing, among others.
Click to expand...

I dont see how this coudl be the problem. I have a gig of ram and windows shows that. I dont see how an video card and PCI stuff could be using close to 2GB of ram.....its just not possable. I dont know what it is, but i know its not that.
 
Okay, then what is it? :p


A 32-bit system can address up to 4GB of RAM. If you have DIMMs that add up to 4GB, then some of that has to be reserved for peripherals like AGP and PCI. They need addresses in main memory.


I remember seeing a mention of this on www.amd.com for example, I'm sure it's somewhere on Intel's site too.
 
sm8000 said:
Okay, then what is it? :p


A 32-bit system can address up to 4GB of RAM. If you have DIMMs that add up to 4GB, then some of that has to be reserved for peripherals like AGP and PCI. They need addresses in main memory.


I remember seeing a mention of this on www.amd.com for example, I'm sure it's somewhere on Intel's site too.
Click to expand...


I understand that, but its certainly not going to use almost 2GB, plus is would still show. The only time memory doesnt show in windows is when it is reserved as video memory for integraded graphics. A laptop with 512MB of ram for example woudl show as having 500MH of ram if it had a 12MB onboard solution. Otherwise, nothing is going to have your ram dedicated to it, so unless he has a 1.2GB onboard graphics card (in other words, a non existant one) that is not the answer. I am guessing it is a regisrty issue since that is where the information is pulled down from, but I don;t know for sure. More importantly, why the hell do you even have 4GB of ram?
 
************************ Alienware Area 51-Extreme [Black] ************************
Windows XP Pro SP2
Intel Pentium 4 560 3.6ghz HT Technology || Intel Pentium I925x Motherboard ||
2GB DDR2 memory || ATI Readon X800 XT PCI-Express Video Card
Serial ATA Raid 0 148GB (74x2) Western Digital Raptor 10,000 RPM with 16MB Cache || Additional Drive - 250GB Western Digital Caviar SE || SoundCard - Sound Blaster Audigy 2 ZS Platinum Pro || Speakers - Klipsch ProMedia Ultra 5.1 ||
Keyboard - Microsoft Multimedia Keyboard - Space Black || Mouse - Microsoft IntelliMouse Explorer 4.0 - Space Black ||
Monitors - Dual Viewsonic VP912B LCD 12ms
*********************************** *********************************** ********************
Click to expand...



what do you possiably need that system and 4gbs of ram for?


don't say server because if you wanted a server you definetly should have gone with a dual cpu setup, and dont say gaming, because no game on earth needs 4gbs of ram to run smoothly with a 3.6ghz and an x800








anyways, i figure that as long as it shows up in the bios it should be accessable to windows xp.

also, try running "Everest Home Edition" (google the part in " " )
 
In a 4GB system, the video card's RAM will have a copy (or sometimes even two!) mapped into system RAM. So will the AGP Aperture/GART. Notice how I said "In a 4GB system."


Let me put it this way: Suppose either of these guys has a 256MB video card, since we don't know. Figure 512MB of RAM reserved right away there. Now suppose they have their apertures set to, oh say 256MB. Another 512MB set aside. Then you've got some more RAM set aside for PCI addressing.
 
sm8000 said:
In a 4GB system, the video card's RAM will have a copy (or sometimes even two!) mapped into system RAM. So will the AGP Aperture/GART. Notice how I said "In a 4GB system."


Let me put it this way: Suppose either of these guys has a 256MB video card, since we don't know. Figure 512MB of RAM reserved right away there. Now suppose they have their apertures set to, oh say 256MB. Another 512MB set aside. Then you've got some more RAM set aside for PCI addressing.
Click to expand...

AGP aperature doesnt reserve your memory. I just went thru chaning my AGP app to 64, 128, 256, and 512MB, the amount of ram windows reported never changed. Add on AGP card DO NOT TAKE AWAY FROM SYSTEM RAM!!!!!!!!! They just dont. His missing ram IS NOT HIS VIDEO CARD, IT IS NOT RELATED TO IT IN ANY WAY! End of story there! PCI adressing also doesnt reserve ram directly from your memory. In your example above, say someone had 1GB of ram, just from the video card and AGP app, your telling me they are down to 256MB, and then the PCI adressing eats up some of that? You sir are wrong!
 
If you're not going to answer me, I'll just point out that you weren't paying attention. First of all it's a copy (of VRAM and GART and PCI, etc.) that gets mapped into the end of system RAM, and second of all everything I've been talking about applies to 32-bit systems with 4GB of RAM.
 
First off, that guy doesn't know what the fuck he's talking about so there is no point in going off on what you don't know about. Secondly, are both you guys having the same problem? If windows is showing that you have 2.8 GB of ram then maybe it's because that's all it can read. I've never heard of this problem though. Never seen anyone with over 2GB of ram in the first place :p. I'll try to find some info for you on microsoft.com to see if there are any problems with SP2 and 2GB+ of memory. It could just be some bug.
 
bboynitrous said:
First off, that guy doesn't know what the fuck he's talking about so there is no point in going off on what you don't know about. Secondly, are both you guys having the same problem? If windows is showing that you have 2.8 GB of ram then maybe it's because that's all it can read. I've never heard of this problem though. Never seen anyone with over 2GB of ram in the first place :p. I'll try to find some info for you on microsoft.com to see if there are any problems with SP2 and 2GB+ of memory. It could just be some bug.
Click to expand...


Same thing I figured, If everything else reports as having 4GB there is really no reason to sweat IMO. I still dont understand why you need anywhere near that much ram, but whatever. Hopefully you can find a fix, but either way, I don't think it matters. There is no way to really test if your system is using 4GB of ram, because unless your running a server, its would be really hard to use up even the 2.8GB you are seeing. If I were you I woudl just return the ram, you dont need it anyways.
 
sm8000 said:
If you're not going to answer me, I'll just point out that you weren't paying attention. First of all it's a copy (of VRAM and GART and PCI, etc.) that gets mapped into the end of system RAM, and second of all everything I've been talking about applies to 32-bit systems with 4GB of RAM.
Click to expand...


No.

A computer Engineer friend of mine just confirmed you are wrong.

That stuff is not mapped into memory.

If you would like to argue with him, I will pm you his office number.

Hope you don't mind calling Florida State University to argue.
 
I'd much rather visit Florida ;)

I get my info from an engineer who designs motherboards and writes BIOS. Here's his quote:

Well, obviously, the graphics card needs to have its RAM mapped into the system's address space. 32-bit addressing gives you 4 GBytes total. Less obviously, graphics cards tend to map two or more representations of their RAM. Add the GART and the AGP aperture, and you'll end up with roughly three times the card's actual RAM size. Eating 1.5 GBytes out of a total 4-GByte address space IS going to hurt. Two problems: Systems with lots of RAM will have to mask off some of it, to make room for the AGP ongoings. Even with that done, there is very little room for mapping of virtual RAM technologies (swapfile et al).

If I have misrepresented what he's said here please let me know - if I'm wrong I'll stand corrected. As for the Abit AV8:

On AMD64 architecture, AGP cards still need to map below the 4-GByte border. But given the 40-bit physical and 64-bit logical addressing you can at least relocate the RAM to above the 4-GByte border, and have your "virtual" RAM up there, even WAY up there above the 40-bit border. Problem solved.
 
sm8000,

I've never heard of any such thing.

Why only systems with 4gb? Why would it not behave the same in systems with a lesser amount of memory? 4 gb is the magic point where the mobo and everything else involved will all of a sudden change the way it handles memory?

How about some links to substantiate what you are saying.
 
Windows XP can have all possibly combinatinos of 32-bit addresses, the number of which can be easily calculated by multiplying 2(the maximum number of options in each slot) by itself 32 times. So, we get 2³²=4294967296 possible addresses, and if each address is only one byte (as it really is), then about 4Gb. Now, that's not only your RAM. the GDDR on your video card also needs addresses, and cache on your CPU, and cache on your hard drives and optical drives. You're fine running over 4Gb memory just like that, however, you'd have a BSOD every time you try to assign more addresses than you can - i.e. - load something that takes up more than 4Gb, alltogether. The system can't hand out an address, and will promptly crash.

This is where one of the main advantages of a 64-bit system come in - way more RAM. Try punching it 2^64 in your calculator... ;)
 
2^64 = 18446744073709551616

according to windows calculator, it might be lying too, but i dont feel like doing it out by hand so i will trust it for now ;)
 
iddqd said:
Windows XP can have all possibly combinatinos of 32-bit addresses, the number of which can be easily calculated by multiplying 2(the maximum number of options in each slot) by itself 32 times. So, we get 2³²=4294967296 possible addresses, and if each address is only one byte (as it really is), then about 4Gb. Now, that's not only your RAM. the GDDR on your video card also needs addresses, and cache on your CPU, and cache on your hard drives and optical drives. You're fine running over 4Gb memory just like that, however, you'd have a BSOD every time you try to assign more addresses than you can - i.e. - load something that takes up more than 4Gb, alltogether. The system can't hand out an address, and will promptly crash.

This is where one of the main advantages of a 64-bit system come in - way more RAM. Try punching it 2^64 in your calculator... ;)
Click to expand...

So wait a sec, it is being stated here that once you have 4GB installed, your whole system dumps everything into ram?

I just don't see why 4GB of Ram would cause a whole set of hardware to act differently.

I will be running an experiment later, I happen to have a buddy with a server. I am going to see if he will bring 4x1024mb sticks of DDR400 over. :)
 
No, but if you were, say to fill up more than 4Gb of ram in total, that includes ram on your video card, and ram on your board - you would still have some ram left (hypothetically speaking, the 256-mb video card is full, and there's only 3.74Gb filled of onboard ram, and 1mb of cache). See, you still have 256Mb of ram left (that's empty), however you don't have any more addresses to go around. So, if one of the programs you're running (or another program) tries to write anything to ram at this point, you would get a BSOD, because M$ writes stupid software. Well, maybe they fixed it, so it won't BSOD, but something evil would definetly happen... either way, you can't use ALL of your ram in that case.
 
Yes, i knew windows xp had problems with more than 4gb of ram. However, I was just wondering what the hell people were talking about when it came to all the ram actually being used by the hardware.

What you said makes sense. But what the other guy said still doesn't seem correct.
 
Well I sent an email to both AMD and Intel tech support asking about this. Intel has responded with the following document:

ftp://download.intel.com/design/motherbd/cv/C6859701.pdf

And told me to start reading at page 55. Here's something just to get started:

my.php


EDIT: Sorry about the shrunken image, I'm open to suggestions for a better hosting site.
 
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