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Have 4Gigs but says I have 2.5Gigs

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November 15, 2007 12:25:27 AM

I just upgraded from 2G’s to 4G’s of Kingston 667, all 4 the same memory, but windows only shows 2.5G’s. I have Windows XP not sure if its 32 bit or 64 bit. After reading what “Scotteq” posted on another post , it seems that 2.5G’s is what it should being saying. Just wanted to know if my system will be using the 4G’s or just use the 2.5G’s or do I need to upgrade my BIOs. Any help would be great. Thanks

More about : 4gigs 5gigs

November 15, 2007 12:47:41 AM

Windows XP Home & Pro is only 32bit, and will only recognize 3.5gigs windows xp 64bit will recognize all 4 gigs
a b } Memory
November 15, 2007 3:18:23 AM

Only 64bit OS recognizes full 4GB RAM
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November 15, 2007 3:48:26 AM

32bit or 64bit, I dunno why it would be showing at 2.5 anyway, doesn't seem right.
November 15, 2007 5:03:34 AM

I agree. A 32-bit OS should show at least 3GB, not 2.5GB. My big question is what video card you are using? If it's integrated, that might explain why it's showing only 2.5GB instead of 3GB.
November 15, 2007 5:25:57 AM

I have the ATI Radeon x300se,its a old card=(. But on the 19th I am going to buy a HD3870. Wow, never thought of the card messing with the ram.
November 15, 2007 5:58:37 AM

you have to take in to account all ram

dvd cache
hdd cache
video cache

subrtact that from 3.5 you have 1gb of cache
November 15, 2007 5:59:24 AM

I have the same problem, if it is a problem, with a recent build for my parents:
q6600
Asus P5B vanilla
4 gigs Patriot
8600GT 512 MB
WindowsXP 32bit

Only showing 2,5 GB RAM. Memory remapping and other BIOS options don't help...
November 15, 2007 6:06:01 AM

Thanks for the info, I will see what happens when the new card comes. If not changes happen might try and get XP64. Thanks again.
November 15, 2007 7:04:07 AM

There are too many PCIe devices on your mainboard, which each will deduct 250MB from your main memory...
try disabling some onboard devices (such as onboard LAN) and see if you can regain some part of the main memory...
a b } Memory
November 15, 2007 7:04:10 AM

This is really simple. Go into the BIOS and see what it is telling you. The BIOS will tell you what the hardware (motherboard and CPU) is seeing, not what the OS is seeing.
November 16, 2007 11:46:24 AM

If you are looking up your RAM on >my computer/system properties.... that RAM will be less if you have shared memory being dished out all over the show a few times on XP my pc has shown 768mb of RAM instead of 1024mb
November 16, 2007 7:24:09 PM

: Will my system recognize the maximum upgrade?

A: Possibly

How much memory your Windows OS will recognize depends on which version of Windows you are running. 32-bit versions of Windows will see (and utilize) only 3GB or 3.5GB. To utilize more memory, install a 64-bit version of your OS. More information about OS memory maximums can be found at http://www.crucial.com/kb/answer.aspx?qid=4251.

This is from the Crucial website. If you go there and scan your computer these FAQ may help solve your problem. It help me with with a similar problem. As others said your system may use .5 gb of RAM and it might not show up on your system check.
November 16, 2007 8:01:25 PM

This is a Windows 32 bit limitation.
First check your motherboard. Many motherboard can only recognize 3GB.
If your motherboard supports 3-4GB, then you may need to modify your Windows system files in order to see beyond 3GB.
a b } Memory
November 16, 2007 8:40:24 PM

akaiello said:
I have the ATI Radeon x300se,its a old card=(. But on the 19th I am going to buy a HD3870. Wow, never thought of the card messing with the ram.


If you have an x300 series card, you should see more then 2.5GBs. These cards had at most 256MBs of memory. Add in other things like I/O, and you should see around 3GBS, probably more. If you know what you're doing, you can go into the bios and disable anything you aren't using.

EDIT: Forgot to mention, you subtract the "cache" amount from 4GBs, not 3.5GBs. A 32bit OS assigns RAM starting with memory address 00000000 and works it way up, while I/O and caches start at FFFFFFFF and works its way down. FFFFFFFF is equal to 4GBs, not 3.5GBs
November 16, 2007 10:08:55 PM

Thanks for all the help! I have tried taking one of the sticks out to see if any changes occurred. Nothing changed still 2.5gigs; do you think one of the sticks was DOA? As for my graphics card it has 128MB DDR video memory, just ordered ATI 3870 should be here on Monday or Tuesday. Not really too confident with my BIOs skills, a little scared to go into them. I was trying to find what key/keys to press to access BIOs but, never had enough time. Pressed pause/break key to try and slow boot up down, but then my screen went out =(, so I stopped messing with the BIOs. I emailed ECS to see if they had any patching to give me, I‘ll keep you guys updated, and try to get into my BIOs. Thanks again for the help.
a b } Memory
November 16, 2007 11:19:10 PM

Ok, let me try to explain this good enough. A computer uses two bits, 1 and 0. If you have 32 of these, then you have 2^32. This comes out to 4GBs. As I said, the OS assigns physical ram from 00000000 and up. (this is the hexadecimal value of writing it.) The OS however needs to read/write information to the video card, or get information from the harddrives, etc. The video cards memory is assigned from FFFFFFFF on down. The more memory your video card and other devices have, the less memory address space is available for your physical. There simply isn't enough address space.

As I said, your video card is rather low end. 128MBs isn't very much memory, so it wouldn't take up very much address space. (as I understand things, it should only be taking up 128MBs of address space.) Along with everything else in your system, it shouldn't take up more then 1GB, so you should see 3GBs+, not 2.5GBs. Depending on what else is in your computer, there might not be any problem at all.
November 18, 2007 6:26:45 AM

Ok, sorry this took so long but I went into my BIOS and found what my memory was. Seems as though the mobo is also seeing 2.5G.
Total Memory= 2621440k=2.5G
Base Memory 640k
Extended Memory=2620416k=2.48G
Current MRC Version 6.4
Current FSB Frequency 200MHz
Current DRAM Frequency 333MHz
Memory Clock [AUTO]

If you need any other info tell me know.
Thanks
November 18, 2007 7:53:48 AM

Your os is not 64 bit.....
November 18, 2007 9:39:04 AM

What is your motherboard it may only support 2G, you may need to reseat the new memory or you got bad memory.
November 18, 2007 10:09:40 AM

The limitation of 4GB address space was introduced in SP2

bios might display the useable amount of ram. If your hardware support more than 4G and memory remapping, you could try and enable remapping to Test if bios will report it all (just as a test, your windows cannot use the remapped ram)
November 18, 2007 11:34:08 AM

Vast majority of people use 32-bit OSs purely for the convenience as u dnt need to hunt down 64-bit drivers which are usually behind the 8-ball as far as features go and often unstable. and thats the limiting factor.
your OS.

because ur running 32 bit XP that limits the RAM that ur comp can access to 4gb. The recommendation is to use 3gb or less of ram. This is because large chunks of memory in the 3gb to 4gb section are reserved for "memory-mapping devices" and scarily this also includes the 128MB to 1GB of memory installed in your graphics card.

If you use a 256MB graphics card, then 256MB of the memory between 3gb and 4gb will be unavailable for you to use, ie. you will only see 3.75GB of usable memory.
For those with less than 4gb of RAM its not eating into that memory, as these devices are mapped: it's virtual address space - your PC thinks it's there but it isn't really, until you actually put that much RAM in. Confused yet?

Now moving onto 64bit OS doesn't change that one bit. You'll get roughly the same amount of available RAM using 4gb of memory under 64-bit as under 32-bit OSs - no advantage there. However, 64-bit allows you to go further than 4gb, so you can start ramping it up again. The price of 2gb memory modules and the support of the motherboard to cater to larger RAM sizes not withstanding.

Looking forward it will be one of those facts we take for granted as history shows these memory maps don't get removed: we just move on past them. So, in a few years time, you'll be installing 8gbof RAM with your 1gb video card and you'll only get 7GB to actually use.

As rule of thumb, its recommended 2gb or 3gb for those building a PC. Seeing as 32-bit vista will limit you to 3.12gb of memory anyway, you wont feel ripped off *as u undoubtedly might be*, and it'll save a bit of money on memory you can't use.

For those going 64-bit... good luck.
a b } Memory
November 18, 2007 12:41:06 PM

akaiello said:
Ok, sorry this took so long but I went into my BIOS and found what my memory was. Seems as though the mobo is also seeing 2.5G.
Total Memory= 2621440k=2.5G
Base Memory 640k
Extended Memory=2620416k=2.48G
Current MRC Version 6.4
Current FSB Frequency 200MHz
Current DRAM Frequency 333MHz
Memory Clock [AUTO]

If you need any other info tell me know.
Thanks


I'm thinking you might need a bios update. The bios should see the full four gigs. Try running with only the new ram, make sure both sticks are good. (just pull the original ram.) Assuming they run fine in the slots they've always been in, I'd look for a bios update.
a b } Memory
November 18, 2007 12:42:32 PM

Rabidpeanut said:
Your os is not 64 bit.....


So? A 32bit OS should see more then 2.5GBs. At this point, we aren't even talking about the OS, but the BIOS. That certainly should see more then 2.5GBs. If the bios is only seeing 2.5, thats why the OS sees 2.5 and not 3.2-3.5GBs.
November 18, 2007 12:43:22 PM

AAAAAAAAAAAUUUUUUUUUUUUUUUUUUUGGGGGGGGGGGGGGGGGGGGGGGGHHHHHHHHHHHHHHHHHHHHHHHH

IF YOUR COPY OF WINDOWS IS 32 BIT VERSUS 64 BIT IT WILL NOT BE ABLE TO USE 4 GIG OF RAM. IT'S THE WAY THINGS ARE. DONT BOTHER. IT WONT WORK. PLEASE FORWARD THIS TO EVERYONE IN YOUR ADDRESS BOOK. LEAVE IT WRITTEN ON POST-IT NOTES IN THE SUBWAY. OPEN YOUR WINDOW AND YELL IT OUT. CUT IT INTO YOUR LAWN. TATTOO IT ON YOUR BACK. I HAVE A DREAM... A DREAM WHERE PEOPLE GOOGLE THIS QUESTION BEFORE ASKING IT THE 47 BILLIONTH TIME.

IF YOUR COPY OF WINDOWS IS 32 BIT VERSUS 64 BIT IT WILL NOT BE ABLE TO USE 4 GIG OF RAM. IT'S THE WAY THINGS ARE. DONT BOTHER. IT WONT WORK. PLEASE FORWARD THIS TO EVERYONE IN YOUR ADDRESS BOOK. LEAVE IT WRITTEN ON POST-IT NOTES IN THE SUBWAY. OPEN YOUR WINDOW AND YELL IT OUT. CUT IT INTO YOUR LAWN. TATTOO IT ON YOUR BACK. I HAVE A DREAM... A DREAM WHERE PEOPLE GOOGLE THIS QUESTION BEFORE ASKING IT THE 47 BILLIONTH TIME.

IF YOUR COPY OF WINDOWS IS 32 BIT VERSUS 64 BIT IT WILL NOT BE ABLE TO USE 4 GIG OF RAM. IT'S THE WAY THINGS ARE. DONT BOTHER. IT WONT WORK. PLEASE FORWARD THIS TO EVERYONE IN YOUR ADDRESS BOOK. LEAVE IT WRITTEN ON POST-IT NOTES IN THE SUBWAY. OPEN YOUR WINDOW AND YELL IT OUT. CUT IT INTO YOUR LAWN. TATTOO IT ON YOUR BACK. I HAVE A DREAM... A DREAM WHERE PEOPLE GOOGLE THIS QUESTION BEFORE ASKING IT THE 47 BILLIONTH TIME.

IF YOUR COPY OF WINDOWS IS 32 BIT VERSUS 64 BIT IT WILL NOT BE ABLE TO USE 4 GIG OF RAM. IT'S THE WAY THINGS ARE. DONT BOTHER. IT WONT WORK. PLEASE FORWARD THIS TO EVERYONE IN YOUR ADDRESS BOOK. LEAVE IT WRITTEN ON POST-IT NOTES IN THE SUBWAY. OPEN YOUR WINDOW AND YELL IT OUT. CUT IT INTO YOUR LAWN. TATTOO IT ON YOUR BACK. I HAVE A DREAM... A DREAM WHERE PEOPLE GOOGLE THIS QUESTION BEFORE ASKING IT THE 47 BILLIONTH TIME.

IF YOUR COPY OF WINDOWS IS 32 BIT VERSUS 64 BIT IT WILL NOT BE ABLE TO USE 4 GIG OF RAM. IT'S THE WAY THINGS ARE. DONT BOTHER. IT WONT WORK. PLEASE FORWARD THIS TO EVERYONE IN YOUR ADDRESS BOOK. LEAVE IT WRITTEN ON POST-IT NOTES IN THE SUBWAY. OPEN YOUR WINDOW AND YELL IT OUT. CUT IT INTO YOUR LAWN. TATTOO IT ON YOUR BACK. I HAVE A DREAM... A DREAM WHERE PEOPLE GOOGLE THIS QUESTION BEFORE ASKING IT THE 47 BILLIONTH TIME.

IF YOUR COPY OF WINDOWS IS 32 BIT VERSUS 64 BIT IT WILL NOT BE ABLE TO USE 4 GIG OF RAM. IT'S THE WAY THINGS ARE. DONT BOTHER. IT WONT WORK. PLEASE FORWARD THIS TO EVERYONE IN YOUR ADDRESS BOOK. LEAVE IT WRITTEN ON POST-IT NOTES IN THE SUBWAY. OPEN YOUR WINDOW AND YELL IT OUT. CUT IT INTO YOUR LAWN. TATTOO IT ON YOUR BACK. I HAVE A DREAM... A DREAM WHERE PEOPLE GOOGLE THIS QUESTION BEFORE ASKING IT THE 47 BILLIONTH TIME.
a b } Memory
November 18, 2007 12:43:49 PM

baddad said:
What is your motherboard it may only support 2G, you may need to reseat the new memory or you got bad memory.


If the motherboard only supports 2GBs (good idea btw, I hadn't thought of that...) why does it show 2.5GBs of ram? If it only supported 2GB, it should show 2GBs, not 2.5GBs.
a b } Memory
November 18, 2007 12:46:29 PM

dengamle said:
The limitation of 4GB address space was introduced in SP2

bios might display the useable amount of ram. If your hardware support more than 4G and memory remapping, you could try and enable remapping to Test if bios will report it all (just as a test, your windows cannot use the remapped ram)


Sorry, this is wrong also. The 4GB "limit" was NOT introduced in SP2. Its been around much longer then that. (was win98 a 32bit OS?) The bios for some reason is only seeing 2.5GBs. Either because the new ram is bad, not working with the older ram, slot is bad, or has an older bios.
a b } Memory
November 18, 2007 12:52:03 PM

jamesro said:

Looking forward it will be one of those facts we take for granted as history shows these memory maps don't get removed: we just move on past them. So, in a few years time, you'll be installing 8gbof RAM with your 1gb video card and you'll only get 7GB to actually use.



AFAIK, this is what remapping does though. It remaps the I/O stuff to above what your RAM is. Lets pretend I use a 64bit OS, and have 8GBs of RAM. With remapping off, I only have ~7GBs showing, because the I/O stuff is still at the 3-4GB range. If I turn it on however, it goes to the end of the memory address space, and I have 8GBs of RAM.

Quote:
As rule of thumb, its recommended 2gb or 3gb for those building a PC. Seeing as 32-bit vista will limit you to 3.12gb of memory anyway, you wont feel ripped off *as u undoubtedly might be*, and it'll save a bit of money on memory you can't use.


Uhmmm, ok? The problem is that he isn't seeing 3.12GBs, or even 3GBs. His bios, which should see the full amount, only sees 2.5GBs. If his bios doesn't see the full amount, then the OS won't either. We need to figure out why his bios only sees 2.5GB and not 4GB.

November 18, 2007 1:00:41 PM

4745454b said:
Sorry, this is wrong also. The 4GB "limit" was NOT introduced in SP2. Its been around much longer then that. (was win98 a 32bit OS?) The bios for some reason is only seeing 2.5GBs. Either because the new ram is bad, not working with the older ram, slot is bad, or has an older bios.


it is well documented that this limitation was infact introduced in SP2. Before it was 4GB+MMIO

If MMIO takes up 1.5GB and bios is showing the useable amount (without remapping)-- then there is nothing wrong.
a b } Memory
November 18, 2007 1:03:11 PM

valis said:
AAAAAAAAAAAUUUUUUUUUUUUUUUUUUUGGGGGGGGGGGGGGGGGGGGGGGGHHHHHHHHHHHHHHHHHHHHHHHH

IF YOUR COPY OF WINDOWS IS 32 BIT VERSUS 64 BIT IT WILL NOT BE ABLE TO USE 4 GIG OF RAM. IT'S THE WAY THINGS ARE. DONT BOTHER. IT WONT WORK. PLEASE FORWARD THIS TO EVERYONE IN YOUR ADDRESS BOOK. LEAVE IT WRITTEN ON POST-IT NOTES IN THE SUBWAY. OPEN YOUR WINDOW AND YELL IT OUT. CUT IT INTO YOUR LAWN. TATTOO IT ON YOUR BACK. I HAVE A DREAM... A DREAM WHERE PEOPLE GOOGLE THIS QUESTION BEFORE ASKING IT THE 47 BILLIONTH TIME.



Sorry spamming artard, THIS ISN'T HIS ISSUE! You might want to try reading about the problem before you go spamming off like you did. EVEN if he has a 32bit os, he SHOULD see 4GBs of ram in his bios. If you bothered to read this thread, you would have noticed when he said,
Quote:
I went into my BIOS and found what my memory was. Seems as though the mobo is also seeing 2.5G.

You can't tweak into windows what doesn't exist in the bios.
November 18, 2007 2:29:34 PM

So you have 2 problem:

1) Your BIOS only recognizes 2.5GB. Hopefully an update can fix this, in which case you will encounter problem 2.

2) You have a 32bit OS. Even if you manage to get problem 1 fixed you will only see ~3.5GB. I would strongly recommend a 64bit OS, not only for the virtually limitless address space but for the for future (and arguably some current) applications and games that will benefit from a 64bit environment.
November 18, 2007 5:20:03 PM

I am building a new PC and I am getting 4 GB (2x2GB) of memory even I am running WinXP-32 bit.

The way I look at it, 3-3.5 GB GB is still better than 2 GB in term of performance. When I will upgrade to 64 bit OS later, my system will be ready. DDR2 memory modules are so inexpensive so it is better to buy now than looking for matching pairs later.
a b } Memory
November 18, 2007 5:24:59 PM

That is certainly one way to look at things. Considering that you can get 2x1GB DDR2 for <$100, or 2x2GB for <$175, it isn't a lot of money for many people. The problem that some of us have when helping on this forum is the people who buy 4GBs, and don't see. (not understanding 32bit vs 64bit.) As long as you are comfortable "throwing away" .5-1GB of ram, then its not a bad idea.
November 18, 2007 5:58:32 PM

Trunkz_Jr said:
32bit or 64bit, I dunno why it would be showing at 2.5 anyway, doesn't seem right.


Are you running Dual 768mb 8800 GTX/Ultras? Cause otherwise I think you should at least see 3Gb...
November 18, 2007 11:51:37 PM

4745454b Thanks for all the help, I took out the old memory and just ran the 2 new ones like you said to, saw they were good. I then put all 4 in, updated my BIOS, then checked in BIOS, said I had Total Memory=3538944k=3.375G, and I am so ok with that. Again thanks for all the help. Have a good one.
a b } Memory
November 19, 2007 4:03:36 AM

Hmmmm. I still don't understand why it doesn't say 4GBs. (I'm also not sure why 3.5389 = 3.375. Doesn't 3.5389 = 3.54?) I would think the bios would say 4GBs, does it show 4GBs during the memory check part of boot up?

As a side note, how much does windows show? Anything over 3GBs would be good, so if you are happy with it, I wouldn't sweat it. 3.25GBs is a number many people say they get when they do this.

Last, I'm glad it seems to be working out for you. I wasn't trying to be an @$$ earlier, I was simply trying to save you the time of weeding out the bad advice from the good. Its good to hear you are back over 3GBs.
November 19, 2007 6:02:38 AM

It's normal for the bios to show how much is available. To have it all available, remapping should be enabled, if available. But that requires an OS that can use it, like 32-bit Linux
November 19, 2007 6:10:41 AM

It has nothing to do with the fact your using a 32-bit Windows OS the problem is most likely motherboard or Bios related. You should check the motherboards manufacture for bios updates to try and correct the problem. You may also wish to take a look at your motherboards specs while on the manufactures home page as your board may not support the amount of memory that you are trying to use as this sometimes will return incorrect information also. Same as with my Ati Radeon X1600 Pro showing up as only 256mb when its really 512mb but my bios is out of date so it doesn't recognize anything over 256mbs. Also a bit of advice if you don't know how to properly flash your bios I would take it in and have it done professionally as it can make your motherboard unusable if you do it wrong.
November 19, 2007 6:29:00 AM

It is both OS and hardware related. As someone previously said, XP+SP2 cannot go beyond 4G, and thus cannot address all 4GB when it also has to address IO devices
November 20, 2007 12:05:20 AM

double-post excised.
November 20, 2007 5:30:28 AM

even with a 64-bit OS u wont be able to use all of the 4gb. the OS just lets u go past 4gb to 8gb of RAM.
memory mapping will still eat into your last part of usable RAM
its just the way things are and we move past them...
im interested to hear from 64-bit OS operators who can see a marginal difference from the OS?
November 20, 2007 10:32:03 AM

4745454b said:
(I'm also not sure why 3.5389 = 3.375. Doesn't 3.5389 = 3.54?)
That bit's easy. 3,538,944 KB / 1024 / 1024 = 3.375 GB exactly.
November 20, 2007 11:22:47 AM

valis said:
AAAAAAAAAAAUUUUUUUUUUUUUUUUUUUGGGGGGGGGGGGGGGGGGGGGGGGHHHHHHHHHHHHHHHHHHHHHHHH

IF YOUR COPY OF WINDOWS IS 32 BIT VERSUS 64 BIT IT WILL NOT BE ABLE TO USE 4 GIG OF RAM. IT'S THE WAY THINGS ARE. DONT BOTHER. IT WONT WORK. PLEASE FORWARD THIS TO EVERYONE IN YOUR ADDRESS BOOK. LEAVE IT WRITTEN ON POST-IT NOTES IN THE SUBWAY. OPEN YOUR WINDOW AND YELL IT OUT. CUT IT INTO YOUR LAWN. TATTOO IT ON YOUR BACK. I HAVE A DREAM... A DREAM WHERE PEOPLE GOOGLE THIS QUESTION BEFORE ASKING IT THE 47 BILLIONTH TIME.

IF YOUR COPY OF WINDOWS IS 32 BIT VERSUS 64 BIT IT WILL NOT BE ABLE TO USE 4 GIG OF RAM. IT'S THE WAY THINGS ARE. DONT BOTHER. IT WONT WORK. PLEASE FORWARD THIS TO EVERYONE IN YOUR ADDRESS BOOK. LEAVE IT WRITTEN ON POST-IT NOTES IN THE SUBWAY. OPEN YOUR WINDOW AND YELL IT OUT. CUT IT INTO YOUR LAWN. TATTOO IT ON YOUR BACK. I HAVE A DREAM... A DREAM WHERE PEOPLE GOOGLE THIS QUESTION BEFORE ASKING IT THE 47 BILLIONTH TIME.


Uh, Dude............
I've got 8gb in my 32-bit Windows OS and I'm seeing it all..................

Uh, Dude............
This guys issue is Mobo/BIOS, A 64-Bit OS Can't help.

I certainly hope that is not your website in your tagline.
If it's yours, remove it. You are killing your business each time you use your keyboard.
If it's not yours, careful - You may be open for liable for causing damage to the owners business.
!