4GB of RAM, only 3,5 GB usable

[Jaakow22]

I recently reinstalled Windows because only 3,5 GB of RAM was usable. After the reinstall, 4 GB was installed and usable, but after a few weeks I noticed that it is again only 3,5 GB usable. I did not change any BIOS settings since I reinstalled Windows. Here is a screenshot from resource monitor:

Like WTF? Any ideas?
Move this thread if it is on the wrong location.
Feedback is much appreciated.

 

[Mellon Head]

It's normal for the system to reserve memory for the hardware addresses. PCs have hardware which is built into the memory map of the computer, like video memory, drive vectors and caches. The OS can't use these areas for standard memory, so it blocks them off from your use.

In any case, it's normal, and nothing to worry about. You can't change it.

 

[LMiller7]

Are you certain you installed 64 bit Windows 7? What you are seeing is typical of a 32 bit OS.

 

[Tookeri]

For 32 bit it would only be able to use 3 GB, while this example shows 3,5 - 3,6

 

[LMiller7]

Having 3583 MB available to Windows in a 32 bit OS is unusual but very possible. Some systems have more. My 32 bit Windows 7 system has 3543 MB.

 

[Berton]

As far as my experience goes, having 32-bit Windows on a computer with 4GB RAM will show only 3.5 to 3.6 available, maybe as low as 3.3GB. Also remember some of the RAM is allocated to the onboard/built-in video by the BIOS before the Operating System loads. Having 4GB on 32-bit doesn't prevent anything, just can't be all used.
Memory Limits for Windows and Windows Server Releases (Windows)
I have a Dell Inspiron 530S on the bench with just that situation with 4GB RAM.
An interesting read, might have to try it on that computer:
http://www.u nawave.de/windows-7-tipps/32-bit-ram-barrier.html?lang=EN
This site is blocking the full URL so take the space out between the u and n.

 

[Tookeri]

If I check in Control Panel - System, it says: 4,00 GB (2,98 GB usable)

Is that showing more too for those of you that are running 32 bit?

 

[LMiller7]

My 32 bit system with 4 GB RAM shows 3.46 GB usable in control panel. If you have 2.98 usable it is likely that a portion of RAM is being used by the video system. This is very common in laptops. The exact amount of RAM that is usable depends greatly on the hardware. Typically it will be about 3.25 GB but it can significantly more or less.

I am not saying that the OP is using a 32 but OS. I just want to be sure that a simple explanation is not overlooked.

 

[whs]

The problem on a 32bit system is not really RAM but address space. I have seen useable numbers up tp 3.6GB. It depends mainly on what the graphics needs.

 

[Tookeri]

Thanks guys, this was news to me.

And apologies to OP for maybe going OT with 32-bit stuff.

 

[Jaakow22]

I have 64 bit version of Windows, but I don't understand how it changed from 4 GB usable to 3,5 GB? I disabled on-board graphics because I was not using it. But how can it change by itself. It was 4 GB usable and now it is 3,5 GB. But how!?!? It was 4 GB after a clean install. And it changed by itself. The thing is that I need that half GB when playing heavily modded Minecraft so I have to allocate 3 GB of ram because other stuff in background and OS are using 1 GB. Because if RAM usage goes over 3,5 GB it goes in Swap memory and I get a nice Not Responding without the progress saved. The graphic card should not take that memory because I have 2 GB of graphics. Should I go check BIOS settings. I disabled on-board graphics, it was 32 MB before now it is 1 MB (it can't be less). But what took that 512 MB of RAM?

 

[LMiller7]

The same factors that limit RAM in a 32 bit OS are also present in a 64 bit OS. The difference being that in a 64 bit OS there is usually a solution. That solution is remapping the inaccessible RAM below 4 GB to an address above 4 GB where it is accessible. This is controlled by a setting in the BIOS. The name of the setting varies from system to system. If the CMOS battery is failing BIOS settings can change for no apparent reason.

 

[Jaakow22]

But still, how can it change by itself, after the reinstall it was available 4 GB but now it is 3,5 GB. How!? There must be something wrong, the CMOS battery is fine, because after playing Battlefield 3 after I take off the headphones I can hear the CPU fan screaming, because it is set on Performance mode, by default it was on silent mode and it was not possible to hear the CPU fan because the PSU fan was way louder. But it was available 4 GB after the reinstall and it changed by itself after a few weeks.

 

[LMiller7]

I found that it is better to check if a setting has been changed rather than try to explain why it could not have changed.

 

[Jaakow22]

No BIOS setting changed.