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Old 07-09-2007, 12:03 PM   #1
pengu
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Unhappy 256m out of 512m RAM detected


Im using linux mint (ubuntu based, kernel exactly the same), The problem also occurs on Ubuntu

My computer is a HP dv1220us laptop:
512MB DDR SDRAM (2 x 256MB) at 266MHz
Intel Centrino 1.5GHz Processor
Intel Graphics Card
Shared 64mb Video Memory

You can visit this link for full specs
http://h10025.www1.hp.com/ewfrf/wc/d...459475&lang=en


Half the time i boot linux, I find that the system has only detected 256mb of ram. I know I have 512mb of ram, and that is what windows detects. Also, the other half of the time linux detects my ram correctly.

This is very annoying and I cant think of any reason why it would sometimes fail to detect half my memory. I do have 2x 256mb sticks in my laptop, could one of those be going bad?

I think this is probably a problem with grub, I belive it is the system which detects the available ram and instructs the kernel how much is available. Correct?

This theory holds as grub does not directly load Windows, it chainloads it. Therefor Windows would not be affected by grubs bad detection of available ram.

But why would it detect it correctly half the time, and incorrectly the other half. I cannot find anything im doing that seems to relate to when the memory is detected correctly.

I have tried adding "mem=512m" to the kernel params in grub, however doing so causes grub to fail to load the kernel saying something like "object will not fit in ram" (i think)

Thanks For your help this problem has really stumped me
 
Old 07-09-2007, 12:40 PM   #2
Quakeboy02
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Do you have two different brands or speeds of memory in that machine? I believe that memory is normally detected by BIOS. Are you sure that the BIOS is displaying the correct amount of memory on those occasions where Linux doesn't sense it properly?
 
Old 07-09-2007, 01:25 PM   #3
pengu
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thanks for the reply, the memory in the pc is the same, in fact, i havent changed it since i bought the pc. Ill check the bios later as i dont have access to that pc atm. I'm doutfull that it is a hardware problem as windows allways shows 512mb and it only sometimes fails to show it all on linux.
 
Old 07-09-2007, 11:37 PM   #4
Wim Sturkenboom
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It does not make sense to me (indeed, check what the BIOS says during the post).

I suggest that you run memtest for a night to make sure that the memory is OK.
 
Old 07-12-2007, 09:18 PM   #5
pengu
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bios checks out ok... im out of ideas
 
Old 07-12-2007, 09:45 PM   #6
lazlow
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Linux actually uses all the memory all the time (one way or another). Windows just lets it set if it does not use it. If the memory is having an intermittent failure windows may not detect it, but Linux will. I would run memtest86+ on it for at least a couple of hours (the version that uses a boot disk). If that comes back clean then it may be a Linux problem, but 99% of the time it is a hardware issue.

Good Luck
Lazlow
 
Old 07-13-2007, 04:09 PM   #7
pengu
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I understand that it really sounds like a hw problem, that was my first consern also.

However, The Bios shows 512, and windows shows 512, linux however (both distos i have on my laptop) show 256 half the time i start them.

I ran memtest (the one installed with linux) a few nights ago, and it showed no errors.
 
Old 07-13-2007, 05:15 PM   #8
lazlow
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How long did you run memtest? It needs to be ran for at LEAST a couple of hours. Many times the errors will not show up until the memory get warmed up.

The bios and windows only check the memory at startup.
 
Old 07-13-2007, 08:42 PM   #9
pengu
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I ran memtest for a whole night..

it really doesnt seem like a memory problem. Browsing the forums there seem a few threads stating that linux detected half their memory, but none of them have been solved.
 
Old 07-13-2007, 08:58 PM   #10
pengu
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sorry guys

just checked my bios again and it showed 256 mem

whats more when i go into memtest, memtest itself only detects 256, which i did not see last time. That would explain why memtest checked out ok

I guess i stand corrected

(just saw u browsing the thread lazlow thanks for the help anyway)
 
Old 07-13-2007, 08:59 PM   #11
lazlow
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Pengu

I go two similar threads mixed up. The other thread was about a memory leak.

Sorry

Lazlow

Edit: I have to learn to type faster. Good that you got it figured out.
 
Old 07-13-2007, 09:01 PM   #12
pengu
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lol np (apperently i need 10 chars to post lol)
 
Old 07-14-2007, 01:59 AM   #13
Kahless
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It might not hurt to reseat both of your memory modules, perhaps switching their positions in the process.

If its still flaking, hopefully its a brand with a lifetime warranty
 
Old 07-14-2007, 09:34 AM   #14
pengu
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yeah hopefully ill take them out, blow on them, then put them back in and have them work

but knowing my luck, ill open the case and found someone has stolen one of my modules
 
  


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