New RAM == unstable 1

[tanderso]

I've got a discussion over in PC Hardware about a problem I'm having with installing a new DIMM. It is looking less and less like a hardware problem, and perhaps could be a problem with the OS. I'm running Mandrake 9.0. Please take a look at that discussion: thread602-436463, and lend your expertise.
Sincerely,

Tom Anderson
CEO, Order amid Chaos, Inc.

http://www.oac-design.com

 

[ag6969]

It's possible it's a motherboard issue or a RAM compatibility issue. In the first place, Athlons are finicky about the brand used, maybe you're mixing brands and have an incompatible brand?? You also didn't mention if the BIOS recognizes 1 GB, you mentioned that only 850MB is recognized in Linux.

For the motherboard, I have had problems with Soyo motherboards based on the Intel i810 chipset for Celerons, where, even with 3 DIMM slots and support for up to 768 MB, I couldn't use 1X128 and 2X64 to get 256, even though Soyo claimed it could. The system just wouldn't recognize the RAM in slot 3. It sounds like you could be having the same problem, and it's more than likely a RAM incompatibility.

Unfortunately, (and probably impossibly), the only other way to tell would be to have a different make/model motherboard, though this would require a separate installation of Linux. If you could spare a hard drive, you try an install of say Windows or something just to see how that reacts.

Running RAM diagnostics aren't going to tell you anything, other than what you already know (the RAM works!), since they generally just fill up the memory addresses with different patterns of 1s & 0s.

I know this doesn't solve your problem, just brainstorming some possibilities. Good luck.

 

[tanderso]

The BIOS does recognize 1G at boot and passes the test. What is it that causes an incompatibility between RAM brands? Aren't they all built to the same specification?

I thought about possibly installing Windows to see if there are problems there too, but I don't have a copy I can pirate for the purpose and I'm not going to pay like $200 for it. If I can find a good memtest program that runs in DOS or something else that fits on a boot disk, I'll try that.

The mem testers that I tried in linux included one which compiles the kernel a whole bunch of times and tests DMA access in addition to CPU access. It passed the memory with zero errors when any two DIMMs are installed, but fails with all sorts of memory errors when three are installed. Like you said, this only shows that the RAM is OK, but doesn't narrow the problem down to the MoBo or the OS.
Sincerely,

Tom Anderson
CEO, Order amid Chaos, Inc.

http://www.oac-design.com

 

[ag6969]

Try DocMemory, it's available from

http://www.simmtester.com,

and it's free. It will create a DOS bootable disk that will start the program, and it's good, although as I stated earlier, RAM testers don't always find fault with these types of issues.

I am not familiar with this motherboard, but have you tried configuring the RAM timings in the BIOS? I don't know what BIOS your mobo is using, so I really couldn't point you to the location to do this. This would be in your mobo manual.
There is usually the option to auto configure, and this is usually best since RAM manufacturers don't usually provide you with that info.

With regard to RAM issues, there are several factors that can cause these problems, timing (CAS and RAS latency, this is the timing I was referring to above), and access times. Access time is measured in nS (nano-seconds), and is USUALLY stamped on the individual chips. The individual chips will usually have some long part number, followed by a -x or -XX where X is a number (6,7,8 etc.) This translates into the access time (-6 = 6nS), but not all manufacturers do that. If all modules don't match, this will cause problems, though newer memory / mobos will just cause all RAM to work at the slowest module's speed with no adverse effects.

I'm not a Mandrake user, but from what I know, there shouldn't be a problem running 1 GB on the stock kernel. In RedHat, you have to recompile for 4GB+. If the BIOS sees the 1GB, and Mandrake only sees 850MB, I would say that MAYBE it's time to look at the operating system. From a console window (or at the console), type "dmesg | more", without quotes. This will show you how much RAM the kernel is recognizing.
Here is a clipped version of my dmesg output, which has 256MB of RAM. I clipped it so the last line is the one you need to look for. (To give an idea of how far down it is.)



Linux version 2.4.18-14 (bhcompile@stripples.devel.redhat.com) (gcc version 3.2
20020903 (Red Hat Linux 8.0 3.2-7)) #1 Wed Sep 4 13:35:50 EDT 2002
BIOS-provided physical RAM map:
BIOS-e820: 0000000000000000 - 000000000009fc00 (usable)
BIOS-e820: 000000000009fc00 - 00000000000a0000 (reserved)
BIOS-e820: 00000000000c0000 - 00000000000cc000 (reserved)
BIOS-e820: 0000000000100000 - 000000000ffec000 (usable)
BIOS-e820: 000000000ffec000 - 000000000fff0000 (reserved)
BIOS-e820: 00000000100a0000 - 0000000010100000 (reserved)
BIOS-e820: 00000000ffe00000 - 0000000100000000 (reserved)
0MB HIGHMEM available.
255MB LOWMEM available.
On node 0 totalpages: 65516
zone(0): 4096 pages.
zone(1): 61420 pages.
zone(2): 0 pages.
Kernel command line: ro root=LABEL=/
Initializing CPU#0
Detected 497.833 MHz processor.
Speakup v-1.00 CVS: Tue Jun 11 14:22:53 EDT 2002 : initialized
Console: colour VGA+ 80x25
Calibrating delay loop... 990.06 BogoMIPS
Memory: 252984k/262064k available (1326k kernel code, 6648k reserved, 999k data, 212k init, 0k highmem)



Again, if it only sees 850MB here, I would look to Mandrake as the starting point. Since you don't have the luxury of multiple mobos and RAM, this might be your only choice.

If you have high speed Internet, you could get the RedHat distro instead of trying Windows. It's totally free, though you would have to download the first 3 isos to install. I'm not saying replace your install, just try RedHat, I've used a stock RedHat kernel with 1GB and had no problems.

 

[tanderso]

Ok, I've compiled 2.4.20, and as I expected, I've caused more problems than I've solved. The good thing is that it does indeed recognize the full 1G from the output in dmesg and top after setting high memory to 4G instead of the Mandrake default of "off". Unfortunately, this didn't help with the crashes and memory errors... they persist nonetheless.

Now, however, I no longer have sound (module didn't compile or something) and my automount isn't working either, so I have to manually mount removable media. Plus the new nVidia drivers I had to download don't work perfectly either (Tux Racer is jittery at the beginning). The old kernel doesn't boot either, despite its modules being in a different directory tree. So, now I'm worse off than I was before... not only can't I use my full 1G of RAM, but now I have no sound, faulty 3D acceleration, and no automount.

Running docmem shows that the MoBo is indeed stable with all three DIMMs under FreeDOS. So this is definitely a linux problem.

Please, does anyone know why there are memory errors using 1G of RAM under linux? Also, if anyone could help me get my installation back in working order regarding sound, video, and automount, I'd really appreciate that too!
Sincerely,

Tom Anderson
CEO, Order amid Chaos, Inc.

http://www.oac-design.com

 

[tanderso]

Is anyone currently running linux with 1G or more?
Sincerely,

Tom Anderson
CEO, Order amid Chaos, Inc.

http://www.oac-design.com

 

[ag6969]

My suggestion was to try this on a seperate hard drive, not the one with your Mandrake install. As long as you installed RedHat to a different partition, you should be able to rescue your Mandrake install though.

As for your booting problem, it sounds like a boot loader problem, unless Mandrake is crashing after selecting it from the boot menu, then it's obviously a more serious issue. If Mandrake doesn't show up in the menu, you would have to add it to the config file for your bootloader. Read the docs for your bootloader unless you are familiar with it.

I'm out of suggestions as far as the 1GB problem. I can only suggest trying this post in the Linux Server forum. Servers are typical situations where 1 GB of RAM is used, so someone there is more likely to have a solution. I have found that problems in the server forum are solved quite quickly, and there are a lot of experts in there.

 

[tanderso]

I don't need RH to "rescue" Mandrake, as the 2.4.20 kernel is working quite well with only 768M installed. I did get sound to work by removing ALSA and installing the emu10k1 driver. Still no automount and 3D acceleration still crashes, but that's not so important right now. I'm not terribly interested in getting the 2.4.19 kernel working again either (BTW, it does load, but the modules aren't found).

I am still interested in getting my additional 256M of memory working though, so I'll try the server forum as you suggested.
Sincerely,

Tom Anderson
CEO, Order amid Chaos, Inc.

http://www.oac-design.com