StarDestroyer.Net BBS

So I just added two more gigs of RAM to my motherboard, which should have brought the total amount up to 4. When I look at what's displayed in Windows XP, it only reads 3.5. I'm pretty sure that I've disabled any integrated hardware, like the onboard video card, so, assuming that's not it, any ideas?

Superman wrote:So I just added two more gigs of RAM to my motherboard, which should have brought the total amount up to 4. When I look at what's displayed in Windows XP, it only reads 3.5. I'm pretty sure that I've disabled any integrated hardware, like the onboard video card, so, assuming that's not it, any ideas?

This is because Windows XP cannot read up to 4GB of RAM. Unless you are using WinXP 64bit, no, you can't.

Fingolfin_Noldor wrote:

Superman wrote:So I just added two more gigs of RAM to my motherboard, which should have brought the total amount up to 4. When I look at what's displayed in Windows XP, it only reads 3.5. I'm pretty sure that I've disabled any integrated hardware, like the onboard video card, so, assuming that's not it, any ideas?

This is because Windows XP cannot read up to 4GB of RAM. Unless you are using WinXP 64bit, no, you can't.

What about adding the pae switch to my boot.ini box and changing the limitation that way? There's also a supposed "fix" to this limitation offered by Microsoft, or so they say...

Superman wrote:So I just added two more gigs of RAM to my motherboard, which should have brought the total amount up to 4. When I look at what's displayed in Windows XP, it only reads 3.5. I'm pretty sure that I've disabled any integrated hardware, like the onboard video card, so, assuming that's not it, any ideas?

A 32-bit operating system can address a total of 4 GB of memory. Your video card most likely has 0.5 GB of memory, so only 3.5 GB of you system memory can be used.

Bah, 3.5 gigs is enough. I was actually using the 64 bit edition of XP for a while, but I got fed up with constant compatibility issues. I'll stick with this.

PAE is actually enabled by default on any 64-bit capable system, so the amount of RAM you're seeing is the absolute maximum you'll ever be able to use under 32-bit XP. There is the /3gb switch, which allows apps to use 3GB of RAM (2GB is the normal maximum), but it can cause performance and compatibility issues elsewhere, so I would only enable it if you desperately need more than 2GB of RAM in any program.

One of my machines has a physical maximum of 2 gigs and the other at 3 gigs. I have upgraded them each to 1.5 Gigs (moving ram around) and have a 1 gig DDR-400 on order from New Egg.

I was planning to upgrade one to 2 gigs and then later buy two additional stick to bring the final one up to three gigs...am I better off just maxing it at 2 gigs as well?

Superman wrote:Bah, 3.5 gigs is enough. I was actually using the 64 bit edition of XP for a while, but I got fed up with constant compatibility issues. I'll stick with this.

Vista 64 should have better compatibility.

A bit off topic. I am thinking of eventually replacing my XP Pro (so I can later have more than 4GB) with either an XP64 or Vista\Vista 64. Which would be better to get? I prefer one that is reliable and has the least compatibility issues.

Vista 64. It's pretty solid, reliable, and has far better driver compatibility than XP64. You're going to get application compatibility problems no matter which version you upgrade to, but it shouldn't be a real problem, unless you're using some older software.

So how do non Microsoft OS' like Linux handle this? Is the RAM limitation caused/regulated by the OS or does it have more to do with the BIOS or hardware itself?

And yeah, XP 64 wasn't too impressive. You'd think most compatibility issues wouldn't exist at this point, but I couldn't even get drivers for my HP printer.

Vista 64 fo lyfe, dog. It's the answer to the question you haven't asked!

Superman wrote:So how do non Microsoft OS' like Linux handle this? Is the RAM limitation caused/regulated by the OS or does it have more to do with the BIOS or hardware itself?

There are actually ways around this so that you can see the full 4GB of RAM. Unfortunately, certain GPU manufacturers have issues handling those cases, and Microsoft kept being blamed for that, so they just gave up.

32-bit systems can address more than 4GB of RAM using PAE. However, there's a lot of brain dead driver writers out there who can't manage to write code that works with the longer addresses required. So when SP2 for XP got released, they locked it down to 4GB, to prevent crashiness.

Destructionator XIII wrote:

Superman wrote:So how do non Microsoft OS' like Linux handle this? Is the RAM limitation caused/regulated by the OS itself?

It is how the hardware works, so any 32 bit OS will have the same limitations.

Vista 64 should work for you though if you wanted to go that route. I've had primarily good experiences with it.

Beowulf wrote:32-bit systems can address more than 4GB of RAM using PAE. However, there's a lot of brain dead driver writers out there who can't manage to write code that works with the longer addresses required. So when SP2 for XP got released, they locked it down to 4GB, to prevent crashiness.

Linux doesn't have this problem of incompatible drivers, since most drivers are included with the kernel, so PAE works fine for handling large memory. Unfortunately, Ubuntu doesn't provide a precompiled PAE kernel, since PAE is incompatible w/ pre-Pentium Pro and some Pentium M's and VIAS I believe. You have to use Fedora, Debian, or compile your own kernel if you want to use a 32 bit kernel w/ >4GB of RAM. Don't know about SuSE.



TL;DR: Provided you have a newer system, the easiest way on Linux would be to use a distro like Fedora which provides 64 bit or PAE kernels on a 32 bit userspace.

I believe Fedora and Debian allow 64 bit kernels on a 32 bit userspace, which is probably the best way to go, since most applications don't support or need 64 bit anyway, and one can run the few 64 bit apps in a chroot.

Debian and Ubuntu don't really support 32 bit apps on a 64 bit install too well (they just compile nearly everything for 64 bit). Not really a problem until you touch commercial software which happens to be 32-bit only (in my case, Xilinx ISE, for programming FPGAs). Adobe just released a 64 bit flash plugin, and Sun has released a 64 bit Java plugin, so the biggest hurdles to a completely 64 bit system are gone except for whatever commercial packages one may use. There are workarounds such as getlibs to install 32 bit libraries and forcing the installation of 32 bit binaries, but I don't like them since I prefer system files always under the thumb of the package manager.

phongn wrote:

Superman wrote:So how do non Microsoft OS' like Linux handle this? Is the RAM limitation caused/regulated by the OS or does it have more to do with the BIOS or hardware itself?

There are actually ways around this so that you can see the full 4GB of RAM. Unfortunately, certain GPU manufacturers have issues handling those cases, and Microsoft kept being blamed for that, so they just gave up.

*cought*Nivida*cought*