4gb of RAM, 2.7gb in Windows XP

Our "pub" where you can post about things completely Off Topic or about non-silent PC issues.

Moderators: NeilBlanchard, Ralf Hutter, sthayashi, Lawrence Lee

Post Reply
RaptorZX3
Posts: 867
Joined: Sat Feb 11, 2006 11:57 pm
Location: Montreal, Quebec (Canada)

4gb of RAM, 2.7gb in Windows XP

Post by RaptorZX3 » Thu Sep 04, 2008 2:51 pm

ok, i think this topic is very common on the web, but i jus wanted to write about that here.

how so i have 4gb now in my computer, but Windows XP (SP2) only display 2.7gb? (i have the 32bit version, home)

is there a way, apart of changing OS, to fix that?

aristide1
*Lifetime Patron*
Posts: 4284
Joined: Fri Apr 04, 2003 6:21 pm
Location: Undisclosed but sober in US

Post by aristide1 » Thu Sep 04, 2008 3:20 pm

You didn't mention if you have integrated video where some amount of main memory is borrowed for the video. Regardless, you won't see much, if anything, above 3.5GB of memory.

2 to the 32 power(bits) = 4GB, the maximum amount of addressable storage in a 32 bit OS. Why Windows routinely shows less is explained by the experts.

RaptorZX3
Posts: 867
Joined: Sat Feb 11, 2006 11:57 pm
Location: Montreal, Quebec (Canada)

Post by RaptorZX3 » Thu Sep 04, 2008 3:37 pm

check my signature?

edit: nevermind, the RAM sticks seem to be corrupted...i tried them on a different computer and they seem to have a problem...
Last edited by RaptorZX3 on Thu Sep 04, 2008 3:43 pm, edited 1 time in total.

sea2stars
Patron of SPCR
Posts: 167
Joined: Fri Sep 01, 2006 4:04 pm

Post by sea2stars » Thu Sep 04, 2008 3:39 pm

Well.. if you need access to more RAM for apps, you can look into the /3GB Switch; the usual 2GB/2GB for user/kernel virtual address space is changed to 3GB/1GB. I'll occasionally use it for CG rendering/calculations/Photoshop at work when I need that extra bit of RAM. It tends to make the system a bit unstable though.

sea2stars
Patron of SPCR
Posts: 167
Joined: Fri Sep 01, 2006 4:04 pm

Post by sea2stars » Thu Sep 04, 2008 3:41 pm

Heh.. yeah. It says 2GB RAM.

NyteOwl
Posts: 536
Joined: Wed Aug 23, 2006 7:09 pm
Location: Nova Scotia, Canada

Post by NyteOwl » Thu Sep 04, 2008 4:19 pm

I have 8GB in my multi-boot system and XP 32-bit only sees 3.25 GB of it. Perfectly normal. Vista 64-bit, Linux, BSD and Solaris see all 8GB.

dhanson865
Posts: 2198
Joined: Thu Feb 10, 2005 11:20 am
Location: TN, USA

Post by dhanson865 » Thu Sep 04, 2008 6:44 pm

http://www.codinghorror.com/blog/archives/000811.html

Dude, Where's My 4 Gigabytes of RAM?

As far as 32-bit Windows is concerned, the world ends at 4,096 megabytes. That's it. That's all there is. No más.

Subtract from that the amount of ram on your Video Card(s). A PC with Crossfire or SLI going can be limited on ram pretty quickly just because you added one to many video cards or bought the latest fancy card with 1GB ram.

NyteOwl
Posts: 536
Joined: Wed Aug 23, 2006 7:09 pm
Location: Nova Scotia, Canada

Post by NyteOwl » Fri Sep 05, 2008 6:02 pm

Yes it's uch like the old MS/PC-DOS machines with 1MB RAM. You only saw 768KB as the top 256K were allocated to BIOS extension space and video memory and a few buffers. You could get the use of it back by remapping addresses above the 1MB boundary.

Ain't technology great? :)

bonestonne
Posts: 1839
Joined: Mon Feb 05, 2007 2:10 pm
Location: Northern New Jersey
Contact:

Post by bonestonne » Fri Sep 05, 2008 6:45 pm

Windows XP 32 bit can only see 4GB of RAM MAXIMUM. don't forget all your system devices.

pending hardware, you may see up to 3.5gb. that's it. 2x32 to get the 4096 stuff is true...but that's maximum. so your RAM works fabulously, and all 4gb are used by the system, but it wont be shown.

there are stupid partial solutions to it, like PAE (Physical Address Extension) and there's something else. You also have the Memory Hole..but seeing all 4GB in Windows will not happen. ever. period.

http://www.brianmadden.com/content/arti ... ally-mean-

helps?

CA_Steve
Moderator
Posts: 7470
Joined: Thu Oct 06, 2005 4:36 am
Location: St. Louis, MO

Post by CA_Steve » Sat Sep 06, 2008 6:44 am

Isn't it 4GB of *memory*, period? You need to subtract all addressable forms of memory in the system: flash on mobo and vid cards, video RAM, etc from the 4GB total to see what your remaining addressable DRAM will be.

thejamppa
Posts: 3142
Joined: Mon Feb 26, 2007 9:20 am
Location: Missing in Finnish wilderness, howling to moon with wolf brethren and walking with brother bears
Contact:

Post by thejamppa » Sat Sep 06, 2008 7:49 am

Yes in 32-bit systems 4096 is the limit. Its simply bit math 32-bit and do the math you get: 4096 MB. 64-bit system limit is on the otherhand 18 exabytes... ( 18 times everything printed in mankinds history roughly ) in theory by bit math.

RaptorZX3
Posts: 867
Joined: Sat Feb 11, 2006 11:57 pm
Location: Montreal, Quebec (Canada)

Post by RaptorZX3 » Sat Sep 06, 2008 1:56 pm

so the "future" is 64-bit OS (since they do exist, but not a lot of peoples use them right now)

sjoukew
Posts: 401
Joined: Mon Nov 27, 2006 6:51 am
Location: The Netherlands (NL)
Contact:

Post by sjoukew » Sun Sep 07, 2008 3:47 am

64bit is more and more used on new high-end systems. Almost all systems with 4gb ram are using 64bit operating systems. As well linux as vista.

Vicotnik
*Lifetime Patron*
Posts: 1826
Joined: Thu Feb 13, 2003 6:53 am
Location: Sweden

Post by Vicotnik » Sun Sep 07, 2008 4:00 am

sjoukew wrote:64bit is more and more used on new high-end systems. Almost all systems with 4gb ram are using 64bit operating systems. As well linux as vista.
I don't know about that. I would guess that most "consumer" systems with 4GB run a 32bit OS. I see ~3.5GB in WinXP 32bit and that's good enough for me right now. Not worth the hassle of WinXP 64bit just for that extra .5GB. I also use the vanilla 32bit version of Ubuntu.

HueyCobra
Posts: 217
Joined: Tue Feb 14, 2006 12:16 am
Location: Australia

Post by HueyCobra » Sun Sep 07, 2008 4:14 am


joelmusicman
Posts: 42
Joined: Sat Jun 18, 2005 6:11 pm

Post by joelmusicman » Sun Sep 07, 2008 5:31 am

Aside from reinstalling, there's actually not much if any additional hassle.

EDIT: besides the issue of ACQUIRING the 64 bit os... I simply "borrowed" a corporate install CD from my company.

Using Vista 64 bit, the only headache that I found was the driver signing issue. Even then, I only ran into the problem when trying to run VMware server. There are workarounds out there, but I was never able to get them to work. I ended up having to use the workstation edition.

I've run office tasks, video encoding, and even 2002-2005 era video games without any problems at all.

edh
Posts: 1618
Joined: Mon Mar 17, 2008 1:49 pm
Location: UK

Post by edh » Sun Sep 07, 2008 7:40 am

You do not strictly need a 64-bit OS to use more than 4Gb of RAM, you can use more than 4Gb of RAM with a a correctly configured 32-bit kernel. There is a set of options when building a 32-bit Linux kernel to select different ways of addressing memory with three limits available, 1Gb, 4Gb and 64Gb. It does not natively address 64Gb of RAM but the kernel has ways round that. It's slightly irrelevant now as if you were running Linux on a system modern enough to have more than 4Gb of RAM, you probably would be running a 64-bit distro anyway.

Post Reply