Double memory, 1/100th the speed!!!
 

Hello ppl,

I have a laptop (private brand, a chinese make I would bet) with the following specs:
P4 2.8 GHz, 512 MB DDR 333, Intel chipset 845G, 60 Gb HDD, 100mb LAN, USB2 and FireWire connections.
It is a dual boot system with SuSE 9.3 and WinXP.
As I am running quite some servers on the machine, it was a little slow and I decided to upgrade the memory. I bought another 512 MB module (not of the same make but of the same specs).
On windoze, the speed increase was obvious after some apps running at the same time.
The problem is on linux. When I have the two memory modules installed, linux takes about 20-25 minutes to complete the boot cycle, and is practically useless when the GUI is up. When I use only one module (whichever, it doesn't matter which, on whichever slot) everything is back to normal.
I tested the memory with some memory testing tools, no problems found. After all it works very nice on windoze.
I cannot find a solution, I've googled on this and there seems to be noone having the same problem.
Please advise...

Iosif

Hi Es_PagAn

I had the same problem with my own setup, which is almost identical to yours. First of all, the memory modules, DIMMS, whatever, mmust be the same type as the originals (the exact same too, I'm pretty sure). I tried in vain to boot debian and suse for some time (they did boot, although VERY slowly). memtest86 which you should find in /bin solved the problem for me, but I also had the exact same Dimms as the originals. Hope it works out for you

Well it is difficult to find exactly the same module, I bought this laptop 1.5 year ago, and it is of a private brand, the store doesn't even have the same laptop anymore.
But the module I have is of the same type, DDR PC2700, CL 2.5
But, if it was a hardware problem, wouldn't it be a problem in general? I mean why do windoze work OK?

Well, I found that passing the parameter mem=960m to the kernel on GRUB did the trick. Everything runs as it should now, except for one thing: the sound is gone!!!
It's a ac97 codec and it will simply not start the sound system.

try using alsamixer as root and turning all the volumes up. also, do (again as root)

rcalsasound restart

This is for the alsa sound architecture only

This won't help either. I am logged in as root, but when I run alsamixer I get

alsamixer: function snd_ctl_open failed for default: Permission denied

rcalsasound restart
Shutting down sound driver/usr/sbin/alsactl: save_state:1163: No soundcards found...
done
Starting sound driver: intel8x0 done

But no sound...

I also found out that my wireless PCMCIA card (U.S.Robotics 802.11g Wireless Turbo PC Card) won't start either.

When I remove the parameter mem=960m from the grub, the system takes an eternity to boot but both sound AND pc card work!!!!!!!

As I said, the system is a laptop which uses 8mb of it's RAM as video ram. So out of 1024 MB of total RAM, 1016 MB are available.
I noticed that while starting, the memory test slows a bit down while testing from 1008 to 1016 MB. That should indicate probably that these last 8MB are not cached. That should also explain why the computer becomes so slow when it is allowed to use them.
I tried to put mem=1008m and the computer runs fast, but as I said, sound and pc card functionality are gone.
So the problem must be in those last 8MB of RAM that when used slows the computer down, when excluded turns sound off...

Strange thing is that windoze are not affected at all...

That is strange. Looks like the sound card and wireless LAN card need to access a specifiic memory range or something, which sounds daft. Both are obviously supported as they worked before you had the _large_memory_problem. One thing I would check is that the DIMMS are identical (manufacturuer included) as this has been known to cause problems (OS-independent) when trying to increase available system memory. Other than that, I'm out of ideas, other than to run memtest86 or something. You can put this option in Grub if you want

kernel (hdx,x)/boot/memtest.bin

I have tested the memory extensively (they are not identical but practically the same). The memory works in windows and it works normally when excluding the specific range. When not excluded it works but it seems that the bios doesn't cache these last 8megs and that is causing the problem with the slowness.
Problem is that the laptop is an OEM so a bios upgrade is rather unlikely to be performed (I don't even know what mobo it has).

But it seems so strange that it should be memory related...