Windows XP reporting incorrect amount of RAM?

notfred

Lifer
Feb 12, 2001
38,241
4
0
I jsut got my new PC, and the BIOS reports (correctly) that I have 4 iGB DIMMs installed. However, Windows XP is saying I only have 3.25GB installed.

How do I get Windows to see the remaining 768mb?
 

notfred

Lifer
Feb 12, 2001
38,241
4
0
Originally posted by: OCZ John
Are you running Intel? That's actually normal.

Yeah, P4 3.8... it's normal to have the wrong amount of RAM reported? You sure?
 

VirtualLarry

No Lifer
Aug 25, 2001
56,587
10,225
126
Originally posted by: notfred
I jsut got my new PC, and the BIOS reports (correctly) that I have 4 iGB DIMMs installed. However, Windows XP is saying I only have 3.25GB installed.

How do I get Windows to see the remaining 768mb?

You don't - you're maxed, unless there's some trick that your mobo/system chipset allows, that would allow mapping the PCI and AGP physical address spaces outside the base 32-bit/4GB physical address space that the CPU uses, by also using PAE on the CPU, and the system chipset decoding the upper address lines and remapping the remapping bus address spaces so that they don't share. Plus, would likely need a mobo-specific custom HAL layer for your NT-based OS. This is extraordinarily uncommon, although I've seen it back in the day - Tricord systems used to make an x86 mobo that had a custom NT HAL written for it, because it had three 8259-compatible interrupt controllers, because it had dual EISA busses.


It's the same exact sort of thing that happened back in the day before local busses, on a 386 or 486 ISA-only machine with 16MB of RAM. Since the ISA bus only supports 24 bits of address, and there is the need due to PC hardware architecture compatibility, to leave the A0000-EFFFF memory addresses open for ROM expansion, and some cards required a memory-mapped 1MB address window, within the ISA-addressable range, which meant under 16MB. "Smarter" chipsets had an option to transparently remap the system RAM that was shadowed by those addresses, out past the end of the 16MB RAM limit, thus still usable by some OSes, although not usable for ISA DMA purposes.

So a similar thing would have to happen with the 4GB 32-bit PCI bus limit, and also utilize PAE to extend the CPU's address range from 32 to 36 bits, and remap either the PCI bus addresses, or move the system RAM shadowed by that address range out to past the 4GB mark. If desktop 4GB systems become more common, this may be implimented, but since Intel had been playing down the possibility of desktop Intel systems ever hitting 4GB, it's not likely to happen soon.
 

Bozo Galora

Diamond Member
Oct 28, 1999
7,271
0
0
Hey, Budman - heres some more hilarious posting from BozoG:
(MUAHAHAHAHA - LOL)

============================
http://vbulletin.newtek.com/archive/index.php/t-7854.html
============================
(Quote)
I note too that you do not just stick in 4gb of RAM under XP. I note for the record, unlikely you need this advice, that the BOOT.INI file needs to be adjusted for this memory sizing.


Seriously?

I spoke with Microsoft and Dell, and no one mentioned that to me. The reason I contacted MS and Dell was because some Windows utilities saw only 3GB, while other utilities saw all 4GB (so I was concerned - but they explained it to me).

I did read where someone adjusted their BOOT.INI file because they were using a program that required the system divide the memory so that 3GB was used for programs and 1GB was used for system.

I also vaguely recall making some sort of adjustment (perhaps in the registry) to do something similar. I'm really not sure (old age). But there is definitely no such adjustment in my BOOT.INI file.

Can you elaborate?

http://forum.aumha.org/viewtopic.php?t=11587&view=next
=====================
Quote:
http://forum.osnn.net/archive/index.php/t-65082.html

This motherboard supports no more than 4GB of RAM and you don't need neither
memory remap nor additional boot.ini switches kinda /3GB and /PAE which are
not relevant in your situation.

Original manual has nothing to say, but similar manual of A8V-E explains
that "Due to chipset resource allocation, the system may detect less than 4
GB of system memory when you installed four 1 GB DDR memory modules."
VIA chipsets aren't alone. The same effect inheres in Intel motherboards and
others. Try VIA 4-in-1 drivers.
=========================

Edit: hahha - lol




 

sharkeeper

Lifer
Jan 13, 2001
10,886
2
0
Read English Much?

Well if you were using this clusterfucker of a network I have to even get here on AT, I'm sure you could do better! :p

/PAE in your boot.ini should fix this.
 

notfred

Lifer
Feb 12, 2001
38,241
4
0
Originally posted by: sharkeeper
Read English Much?

Well if you were using this clusterfucker of a network I have to even get here on AT, I'm sure you could do better! :p

/PAE in your boot.ini should fix this.

/PAE doesn't do anything useful. It jsut adds "Physical Address Extension" to the "My Computer" screen, right below where it says 3.25GB of ram.
 

sharkeeper

Lifer
Jan 13, 2001
10,886
2
0
You may have to use the /3Gb and /PAE switch as well.

It could very well be a system issue. I had a roomful of X5DAE's that would show 3.25 as well and added these switches per SM and MS.

This is the result. System sees full 4GB and each application can use a full 2GB each.