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4GB Ram but 2GB Available? (Win 7 Home Premium)

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January 16, 2012 6:26:00 PM

Hi, I've recently built my own PC, It's been perfect, games run well, nothing so far has been an issue, the only thing that is slightly worrying me is the fact that when I go onto any benchmarker, it tells me that I have 4GB of RAM Available (Which I installed) But only 2 GB of the ram is being used. Well, 2.5 to be exact. Is there any reason for this happening? The RAM is all installed correctly and not bent or buckled.

Does anyone have any ideas? Oh, and MSconfig, under advanced settings, is unchecked under the heading: Maximum Memory Allowed.

Any Ideas?

Thanks in advance :) 
January 16, 2012 6:36:40 PM

I have a question. Does this computer have an external gpu or is the video on board? Im guessing the your version of windows us 32 bit? Here are a couple of possibilities. You have an on board gpu that is eating shared memory along with other hardware resources. This makes it possible for windows to only address 2.5 GB of memory. This was a common problem with 32 bit OS from Windows. Quick and dirty to get rid of the problem. Upgrade to 64 bit windows 7 .
January 16, 2012 6:37:34 PM

twofatslugs said:
Hi, I've recently built my own PC, It's been perfect, games run well, nothing so far has been an issue, the only thing that is slightly worrying me is the fact that when I go onto any benchmarker, it tells me that I have 4GB of RAM Available (Which I installed) But only 2 GB of the ram is being used. Well, 2.5 to be exact. Is there any reason for this happening? The RAM is all installed correctly and not bent or buckled.

Does anyone have any ideas? Oh, and MSconfig, under advanced settings, is unchecked under the heading: Maximum Memory Allowed.

Any Ideas?

Thanks in advance :) 


I thikn your issue is that you are running a 32 biit OS.... which can only "see" 4GB max. So although you have only 4GB... th eOS has to reserve space for motherboard devices and graphics etc... so if you have a 1GB graphics card... that would have to be allocated from the 4GB address space that a 32 bit OS can "see".

e.g. My laptop has 4GB mem - but only reports 3GB becasue it needs reserve 1Gb.... I guess your system needs reserve 1.5GB for all your other stuff.

If you had a 64 bit OS - you woul dnot have the issue - it can address so much space you are HIGHLY unlikely to ever hit its limit.

HTH
Cheers
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January 16, 2012 9:31:13 PM

If your on 32 bit it should still show around 3.2Gigs but what you might be able to do is go into your BIOS and theres an option called something like Memory Limitations or something I can't really remember but if thats on I would turn it off and you should see all of your memory.
January 17, 2012 9:31:35 AM

drew13 said:
If your on 32 bit it should still show around 3.2Gigs but what you might be able to do is go into your BIOS and theres an option called something like Memory Limitations or something I can't really remember but if thats on I would turn it off and you should see all of your memory.


Thats rubbish.... First... Whay you say "should still show around 3.2Gigs"? thats just wrong... it will depend on his Mobo and hardware config.
Second....your option re BIOS ... wont work. Its a 32bit/windows limitation... windows cant handle so faffing around in BIOS wont fix that.
January 17, 2012 11:41:35 AM

First and formost, are you on a 32-bit OS? If so, there is a hard cap of 4GB that can be used. Furthermore, after all the hardware mapping is done, you will have significantly less then that.

Secondly, you need to ensure that "memory remapping" is enabled in the BIOS, to make sure that any PCI buses are mapped above the 4GB boundery, which can eat into the total amount of RAM avaliable for use, even on Win64. This is due to PCI specifications that require the PCI bus addresses to be mapped below the 4GB range, so with only 4GB installed, the PCI addressing eats into the maximum total amount of usable RAM unless memory remapping is enabled.

Finally, theres an even simpler explanation:

http://brandonlive.com/2010/02/21/measuring-memory-usag...

Quote:
Free – This one is quite simple. This memory has nothing at all in it. It’s not being used and it contains nothing but 0s.

Available – This numbers includes all physical memory which is immediately available for use by applications. It wholly includes the Free number, but also includes most of the Cached number. Specifically, it includes pages on what is called the “standby list.” These are pages holding cached data which can be discarded, allowing the page to be zeroed and given to an application to use.

Cached – Here things get a little more confusing. This number does not include the Free portion of memory. And yet in the screenshot above you can see that it is larger than the Available area of memory. That’s because Cached includes cache pages on both the “standby list” and what is called the “modified list.” Cache pages on the modified list have been altered in memory. No process has specifically asked for this data to be in memory, it is merely there as a consequence of caching. Therefore it can be written to disk at any time (not to the page file, but to its original file location) and reused. However, since this involves I/O, it is not considered to be “Available” memory.

Total – This is the total amount of physical memory available to Windows.

Now, what’s missing from this list? Perhaps, a measurement of “in use” memory. Task Manager tells you this in the form of a percentage of Total memory, in the lower right-hand corner of the screenshot above. 71%, in this case. But how would you calculate this number yourself? The formula is quite simple:

Total – Available = Physical memory in use (including modified cache pages).


So even if you are running Win64, the amount of avaliable RAM will be significantly less then 4GB, especially since Windows is now very agressive in pre-caching RAM. Avaliable for use does NOT mean total usable by the system.
January 17, 2012 12:28:59 PM

Lordy me....

First... 32 bit OS.... 4GB is the limit in windows. All his hardware mapping needs come out of that.... so dont confuse the guy with talk or remapping.

Second... remapping above the first 4GB can only be done if you have a 64 bit OS...... http://support.microsoft.com/kb/929605

Third.... "So even if you are running Win64, the amount of avaliable RAM will be significantly less then 4GB"... rubbish!!! Win (esp 7) will aggresively cache.. but if you need the memory... Windows will make it avail.... until you run out. So saying its "not available" is disingenuous!!

Now lets leave it before the poor OP head explodes.
January 17, 2012 5:59:19 PM

^^ If RAM is being used by some other application that is running, its not avaliable to you. Unless you want to bring paging into the discussion...

And be careful about confusing "memory" and "address space", something a LOT of people here do.
January 17, 2012 6:06:56 PM

Yes, Win7 is very good at using memory. The more memory you install, the more it will use. It will use for all sorts of caching and whatnot - this makes your computer faster because it keeps more data preloaded onto the memory. You can find more info on google, I'm by no means an expert.
February 13, 2012 4:47:15 AM

yoji said:
Thats rubbish.... First... Whay you say "should still show around 3.2Gigs"? thats just wrong... it will depend on his Mobo and hardware config.
Second....your option re BIOS ... wont work. Its a 32bit/windows limitation... windows cant handle so faffing around in BIOS wont fix that.

I just went from windows 7 32-bit to windows 7 64-bit and 32 bit only recognized 3.2 gigs of ram, I researched all of the internet and 3.2 gigs is the limit for all 32-bit systems (besides something like windows 7 starter).
!