Quick question. Again

Tvangeste

I just got my new parts and rig going and it runs great, no hitches. But for some odd reason XP says I only have 2.75gb of RAM instead of the 4Gb that I installed. Now, it is saying over 2gigs, so I assume that both sticks are working properly. So why would it just say 2.75 then? I'm wondering if this is a XP problem or something. Any solutions, comments. Or am I just dumb about something. XP 32bit. I anticipate some feedback, this is really bothering me. Thanks guys.

Crazed Modda

This is coming directly from a memory manufacturer website.


Its been a known hiccup for quite some time.

Tvangeste

Even though it only sees 2.75. Does the computer still use all 4gb? I would assume that even though the computer only sees so much, does it still use 4gb of RAM?

Tvangeste

I just read a few things and saw that it doesnt work. It says 2.75~3.5. Is there anyway to get mine up to 3.5?

ugzkmk

mine tells me 3,668,384 out of 4gb. i would say try and update your bios. the limitation is a combo of 32bit architecture and limits imposed by the bios. while windows is the main culprit, it could be your bios thats keeping it from getting to that 3.5 mark.

Nicholas.Sexton

Windows 32 bit can only allocate to 4 gb of ram. The 4 gb of ram is a combination of video memory, system memory , cache and etc. So I guess use a video card with a small amount of memory?=P I have 4 gb of ram with a 512 mb video card and my computer can allocate to 3.3 gb.

ugzkmk

there was also a boot.ini switch you could tack on to your main OS, but i personally never messed with it.

Tvangeste

Ive seen quite a few other people with 4 gigs and it all reads 3 gigs or over. Any idea on why mine is stuck at 2.75? And is there anyway I can etleast get it to 3?

LiquidCh@os

The way this works is when a 32bit OS has 4GB of RAM installed it can only use so much of it. The RAM is still there and in fact still in use. Think of it like a partition, the system allocates X ammount of RAM for special use and you get whats remaining.

Tvangeste

Oh. So in fact my system still has 4gbs of RAM and can use it? Even though it only says about half of it is there?

Nicholas.Sexton

Just moved to Vista SP1 and now my computer says I have the 4 gb.

I know before SP1 my computer had the same issue as XP. Maybe they fixed the problem for XP is service pack 3?

WhiteBoy88

Your 32-bit system is, in fact, using every bit of the 4GB. A 32-bit system uses 32b to refer to each memory location. 2^32=4.2 billion is the common equation that shows the possible number of memory locations that a 32-bit operating system can address (it's actually 4.294967296 billion).

The reason it doesn't show you the entire 4GB is because it's already reserved some of it. Input/output devices that use memory get "mapped" which effectively reserves that amount of RAM for the device. This is memory-mapped input/output, or MMIO. A 128MB video card gets mapped to 128MB of physical system memory, as an example. The number differs for different systems because of this. Another thing that reserves memory is Data Execution Prevention, or DEP. This is a security feature that helps detect malware and prevent it from running itself.

Now for the fun part, what you can change:
You can enable Physical Address Extension, PAE, by using the /PAE switch in your boot.ini. This makes the OS use more memory tables to address extra memory. This is one way servers use more memory in a 32-bit operating system. Keep in mind that if DEP is enabled, PAE is enabled as well by default.

To enable PAE with DEP turned off:
Run -> BCDedit /set nx AlwaysOff
then
Run -> BCDedit /set pae ForceEnable

You can also reduce the maximum amount of RAM Windows is allowed to use for system processes (kernel), which might possibly free up memory for user-based applications. I've shown how to do that here. Keep in mind that this does not reserve the memory for Windows. It is free for applications to use until Windows needs it.

Lastly, the Geil link has some bad info on it. It refers to MMIO as a "well-documented problem" with "no guaranteed fix." That's a little harsh..... take away MMIO and your hardware won't work right with Windows. MMIO isn't a problem, it's a solution. That page also tells Vista users to Run -> "BCDedit /set PAE forceenable" to enable PAE. This is unnecessary in Vista, as PAE is already enabled by default. The 4GB limit is software-based in Vista (thanks, Microsoft, we have to "upgrade" our version to get more than 4GB! ).

WhiteBoy88

With that, they simply changed the display option. With Vista SP1, it now shows the amount of installed memory instead of the amount of usable memory. Your system is still reserving memory as usual.

Tvangeste

I just tried this:

To enable PAE with DEP turned off:
Run -> BCDedit /set nx AlwaysOff
then
Run -> BCDedit /set pae ForceEnable

I typed in BCDedit and then /set and so forth first and it gave me the error. Then all I typed in was BCDedit and it still came back as an error.

The thing you showed me. Says the run command can not find that, and asked if my typing and spelling was correct. Am I missing something? This was suppose to be ran in the run command correct?

WhiteBoy88

That's my fault; I got ahead of myself and gave you misguided information. BCD is a lot more in-depth than I implied, and really isn't an average-user tool. If you want to read up on it, check here. It has to deal with setting boot configs, mainly used in driver and software testing.

Tvangeste

Ahh I see. Well, I think I got the jist of how everything works now. I also understand about whats going on with my RAM and how much it is used and all. So I thank you guys for helping out, I'm fairly content with how it is now. Thanks again for your help.

furball zen

Theres also this for x32 and this for x64 arch's.
I actually have 5 gigs total physical memory (4g system, 1g vid) and it only shows 3.0G total.

LiquidCh@os

With regards to PAE, there is no proof of an increase or decrease in perfomance, however it can increase the available ammount of RAM for applications. Just remember tho, maxing RAM out with PAE enable or not will result in a sluggish system.

Hb-Tech

Let us know about ur system configration.
Because some system can not support above 2 or 4 gb ram.