Available RAM Question

[proxima_centauri]

Hi laruesa,

Welcome to Linux Mint.

Just like with Windows, in Linux there are 32-bit and 64-bit versions.

Linux Mint main edition will recognize just over 3GB, but not all 4GB - just like in Windows; however, if you were to install the 64-bit edition of Linux Mint (currently only Linux Mint 6 64-bit is out, with Linux Mint 7 64-bit in the works) then you would be able to see + use all 4GB of RAM.

[emorrp1]

Yep, although I've noticed the answers to these before, including methods for bypassing the restriction (PAE in server kernel), I've never seen anyone actually explain WHY there's a huge hole, until now, enjoy: http://www.dansdata.com/askdan00015.htm

[Fred]

laruesa,

The recognized/OS available memory to the end user is more of a hardware and addressing issue.

In a 32 bit system, regardless of the OS, only 4 Gig can be addressed at one time, total. The OS needs some addressing space for itself and the hardware in the system needs some addressing space also. What is left is about 3 - 3.5 Gig.

There are various work-arounds that an OS can and does use to maximize the user available addressing space, but the base limitation is still there. Windows and Linux both have pretty much standardized on a total address space of 4 Gig. total for hardware and software for a 32 bit desktop system.

In Linux you can add additional patches to the kernel, PAE patches, that will enable you to recognize more address space, but they have a speed penalty and other limitations.

With common availability of 64 bit systems getting better all the time there is less need to try to develop better ways of tricking the 32 bit limits.

Fred

[emorrp1]

hey again laruesa, Mint doesn't release beta versions. What you saw was the Release Candidate announcement, which means it'll become the main release with little to no changes, as it's passed internal tests, and just needs to be verified by the community (the many eyes makes bugs visible principle). This means it's quite safe to install, but you may want to wait for the official release anyway.

[kmrdeva]

Linux Mint main edition will recognize just over 3GB, but not all 4GB - just like in Windows; however, if you were to install the 64-bit edition of Linux Mint (currently only Linux Mint 6 64-bit is out, with Linux Mint 7 64-bit in the works) then you would be able to see + use all 4GB of RAM.

Hmm, I wonder why my 4GB Gloria x64rc1 OS showed only 3828MB RAM even though I've 'disabled' my Intel DG45ID's onboard display (i.e. shared memory) and popped in an NVidia 9500GT card. Should it not detect all 4096MB of the memory?

Just this morning, I had upgraded my PC to 8GB RAM - now the OS sees 7822MB instead of 8192MB.

Any ideas, anyone?

[emorrp1]

kmrdeva: see the link in my post above for an explanation of the "missing" 270MB.

[Fred]

Sometimes the answer to a question is not as simple as one would like it to be. If you didn't like my generalization, then you will just have to dig in and uncover the bolts and nuts that emorrp1 referred you to. That is especially true when you are looking for a mere 2 or 300 MB out of 8 Gig.

Fred

[kmrdeva]

emorrp1 : I just clicked through to read the article. Yep, it was a real eye-opener. So it looks like the missing 370MB from my 8192MB has been used for peripheral mapping (e.g. my 512MB graphics card).

Fred : It's only 4.5% of my total memory so I guess I can live with it. This the the reality of computing, I think..

[bbmidi]

HI all,

Found this thread which is exactly my same problem. From 2gb to 4gb ram Helena 'only' reports about 3gb ram. I read the askdan.com link as well and it is informative.

I tried to install Helena 64bit but it complained my system is just 32bit. It is a laptop dual-core Acer Aspire. I'm not in the machine right now and cant post the full specs. Anyone knows how to get around this issue? It would be great to switch to 64bit to fully utilize my RAM.

TIA.

[kmrdeva]

I tried to install Helena 64bit but it complained my system is just 32bit. It is a laptop dual-core Acer Aspire. I'm not in the machine right now and cant post the full specs.

Do check what processor your Acer Aspire has - it may not be a 64bit-capable processor. I just recently bought myself a spare laptop (cheap, at USD380) which comes with an Intel T4300 processor, 1GB RAM and a 250GB SATA HDD, and thankfully, it works really fine with Helena 64 bit.

[bbmidi]

Thanks kmrdeva will check it out.

Aside from uname what do LM folks use to check processor info, among other things? I'm talking in the CLI of course not GUI. dmesg also comes to mind but grepping only for the needed info is quite an overkill.

In my experience with other debian distro infobash is quite handy. Havent checked if there is equal in LM. Thanks.

[emorrp1]

Code: Select all

inxi -F

will give you a run down of your specs. Note that a "Core Duo" model is 32bit but a "Core 2 Duo" is 64bit.

[bbmidi]

Here's my specs. As you can see free reports 3gb only. Clearly my system is 32 bit. Does this mean i'm losing 1GB due to the limitation? TIA.

Code: Select all

# inxi -F
System:    Host CC00002695 Kernel 2.6.31-14-generic i686 (32 bit) Distro Linux Mint 8 Helena - Main Edition
CPU:       Dual core Pentium T4200 (SMP) cache 1024 KB flags (sse3 nx lm) bmips 7980.42 
           Clock Speeds: (1) 1200.00 MHz (2) 1200.00 MHz
Graphics:  Card Intel Mobile 4 Series Chipset Integrated Graphics Controller X.Org 1.6.4 Res: 1366x768@60.0hz 
           GLX Renderer Mesa DRI Mobile Intel GM45 Express Chipset GEM 20090712 2009Q2 RC3 x86/MMX/SSE2 GLX Version 2.1 Mesa 7.6 Direct Rendering Yes
Audio:     Card Intel 82801I (ICH9 Family) HD Audio Controller driver HDA Intel
           Sound: Advanced Linux Sound Architecture Version 1.0.20
Network:   Card-1 Attansic Corp. Device 1063 driver atl1c v: 1.0.0.1-NAPI at port 1000 
           Card-2 Atheros AR928X Wireless Network Adapter (PCI-Express) driver ath9k
Disks:     HDD Total Size: 250.1GB (6.5% used) 1: /dev/sda TOSHIBA MK2555GS 250.1GB 
Partition: ID:/ size: 30G used: 3.7G (14%) fs: ext3 ID:/home size: 50G used: 12G (25%) fs: ext3 
           ID:swap-1 size: 5.00GB used: 0.00GB (0%) fs: swap 
Info:      Processes 158 Uptime 10 min Memory 349.3/2955.6MB Client Shell inxi 1.2.6

#free

             total       used       free     shared    buffers     cached
Mem:       3026528     765116    2261412          0      19636     380516
-/+ buffers/cache:     364964    2661564
Swap:      4883720          0    4883720

[rekik]

CPU: Dual core Pentium T4200

So it's a 32 bit processor

[kmrdeva]

Here's my specs. As you can see free reports 3gb only. Clearly my system is 32 bit. Does this mean i'm losing 1GB due to the limitation? TIA.

The Intel T4200 in your laptop supports 64bit, according to this - http://bit.ly/5Qmgkq. I'm unsure why a 64bit OS won't load on your laptop, though. A 32bit BIOS perhaps?

3GB seen out of 4GB is a bit too much, I agree. My other laptop with 4GB RAM has a similar issue - only 3.5GB is seen by Windows 7 64bit, and my home PC which has 8GB RAM, shows only 7.6GB in Mint7 64bit. Your case may not be an OS issue, but a hardware architecture limitation.

[bbmidi]

Thanks for the link kmrdeva.

If mine is hardware issue e.g. 32 bit BIOS is there a way to change to 64 bit? Update BIOS perhaps? Yep losing 1GB is a bit too much, maybe 400-500MB i can live with, i dont mind being generous

I'm sure 64bit OS is a no go when i tried installing on my laptop. First was LM8 then arch also 64 bit in virtual machine. Both complained.

[kmrdeva]

I'm sure 64bit OS is a no go when i tried installing on my laptop. First was LM8 then arch also 64 bit in virtual machine. Both complained.

Can you tell me the exact model number of your Acer Aspire? Let's hope that there is a BIOS update for you..

[bbmidi]

Acer Aspire 4736Z.

[kmrdeva]

Acer Aspire 4736Z.

I checked at http://www.acer.com/worldwide/support/download.htm, under Asia Pacific (I'm in Malaysia so that was the most obvious choice) and found that there is a new BIOS update, version 2.06 (dated 14/Dec/09) for the Aspire 4736Z. Update at your own risk, though.

[bbmidi]

Thanks man for the Acer link. I have same version number in my location. I can fetch it anytime when needed.

Funny on the disclaimer thing . Obviously this is do-at-your-own-risk thing. Arent there any fallback or rollback guarantee? Has anyone in the LM forum got a success story on this exercise? I sure love to hear it.

I'm looking for a bios-update-howto in Linux. My laptop is Linux Mint only, no dual booting with MS (so no dos mode or anything). If there is any in LM i appreciate the good folks pointing me to it. TIA.