Hi there,

first: nice new site!
second: ahhhhh!

ehrm... Well, I wanted to put a 1GB module into my PegII since it simply took forever to compile and since I'm playing around with different "hardened" stuff I recompile often... OK, and I like using KDE which doesn't make it better *g*

I choose a Kingston module with 2.5-3-3 timing. To be precise: KVR266X64C25/1G. Now I have three problems:

* it won't work together with the original 256MB module - it simply won't bring up the openfirmware screen (which is btw a 1.2).

* but worse: it has severe problems when using a higher memory area. With the 1GB module the Pegasos starts but as soon as a certain amount of memory is used I get segfaults and different md5sum with every loop. Not good... :-/

* Even after getting a second 256MB module I can't use the now two 256MB modules together. The same problem as above with segfaults.

The modules are ok - tested with memtest on an x86 PC. memtester in userspace on the Pegasos throws errors (not with 1 single 256MB module but with 2 of them or with the 1GB module - 1GB + 256MB won't boot as already mentioned).

Is this a known problem? What should I do?

Thank you!

PS: I'm willing to dump the 1GB Kingston module if someone can give me the exact name etc. of a working GB-module which I could then buy instead. I simply hope my board has problems with this specific module and not with GBs itself (since I already read about Pegs with 1GB RAM. Hmm, should I look at 2GB? ).

oh no...

I organized another memory bank (Kingston KVR333X64C25/512 = 512MB) with Samsung chips onboard. Togehter with the original 256MB bank the Pegasos is booting. But already segfaults while booting. Putting the 512 MB module alone onto the mainboard linux boots fine but memtester throws errors just like with the 1GB module.

Sorry to say it like this but: please help me - I'm going nuts

Thanks for reading!

M

what linux distro do u have installed on your peggy ?
have you enabled high Mem support in your kernel ?

Actually this is nothing to do with Linux.

There is a firmware issue whereby mismatched DIMMs won't be configured correctly. Newer firmwares will flatly refuse to configure mismatched DIMMs and fail before they get to the firmware. It is to do with timings and certain quirks of certain DRAM chipsets.

The current recommendation is to use identical pairs of memory (two 256MB sticks of the same brand etc.) or single sticks.

Hi,

thank you both for answering.

KERNEL:
The distribution is gentoo - the kernel is configured correctly. I even disabled preemption . But even when the error would lie within my kernel configuration (which I don't want to exclude of course), why can't the Peg boot with specific combinations? And why would my kernel identify other combinations correctly (meminfo) but then making bogus with the data?

FIRMWARE:
As the error lies within the firmware using two modules, why does my 1GB module has problems when inserted alone? Shouldn't it work?

UPDATE:
And are there already plans for getting this fixed within a forseeable future? (I don't ask for release dates, that won't work )

Thank you,
M

>There is a firmware issue whereby mismatched DIMMs won't be configured correctly.
>It is to do with timings and certain quirks of certain DRAM chipsets.

When using 2 DIMMs the firmware should surely be able to use the settings of the slowest module?

>The current recommendation is to use identical pairs of memory (two 256MB sticks of the same brand etc.) or single sticks.

I tried it one year ago with 2x 512MB sticks, same brand, same type, same timings, same chip count (16) and it did not work with Peg2
while they run perfectly in a dual-channel AthlonXP board at full DDR400 speed with SPD-provided access timings of 2,5-3-3.
Has this matter changed now and how is your little RAM laboratory project going?

If possible, I would like bplan to certify/validate the RAM from MDT.
They are located between Frankfurt and Oberhausen (*hinthint*) and have a good reputation.
Datasheets with timings etc. are also available.

(I used one of their 256MB "PC150" SDR DIMM in Pegasos I and now a single 512MB DDR400 DIMM in Pegasos II.)

You can do two things (even more) to move up to 1GB RAM:

Just get an additional stick of 512MB memory from a Samsung memory distributor. My Peg II has Samsung Part# K4H560838D-TCC4 which is the 512MB 184-pin DDR400 memory stick. This way you don't have to toss your default memory stick out.

If you want to go with 1GB RAM in one slot (so MorphOS and Linux works well), then you could try:

http://store.yahoo.com/memx/xda10241.html
1GB PC2100 CL2.5 non-ECC non-Registered DDR266 DIMM (p/n ACI)
(haven't tested this myself)

You could put the full 2GB RAM (1GB per slot) in your memory slots, as long you use the same memory brand and part # in both slots. Doing anything else will just cause headaches for you and your machine.

Genesi (or Freescale) has a list of compatible memory sticks to chose for the motherboard and vendors. I'd say the Samsung memory is some of the better memory sticks.

_________________
Pegasos II