OK, it's an old(ish) machine.

AMD Athlon XP 2000+ (1.6GHz)
MS-6382E Ver 3 motherboard
Mandriva 2007 spring (I had upgraded the kernel to 2.6.26.3

There were 2 184 pin slots for containing 256 MB ram. I put in 2 184 pin 1GB DIMM DDRs. Everything seemed fine at first, but then firefox and konquerer started crashing, gunzip and bunzip2 started deciding that loads of files were corrupted, and the C compiler started giving installing things through Drakconf started acing up.

I really want the extra RAM for some heavy electromagnetic calculations.
Anyway, I put the two 256Mb back in, and things seem to be "fixed".

Is there any way I can get the PC3200s to work (pc2700 and PC2100 compatible) or have I messed up bigtime.

From observation only, Linux appears to be really sensitive to memory mismatch - even supposedly same type from the same manufacturer.
Try one stick at a time.

Memtest may or (usually) may not show a problem.

I shall try just 1 then

memtest doesn't appear to exist on my machine though, the new memory showed up nicely on Drakconf though.

Most (disro) install disks and liveCD have memtest as a boot option - it runs "stand alone" so it can test all the memory.

I agree memtest is the way to go, but you need to let it run for a long time (as in overnight) for it to catch all the errors. Make sure you close the case back up and have the same conditions the machine will experience while running (monitor on, all electrical loads on, etc).

I just downloaded memtest86 from memtest86.com. It just didn't come with Mandriva 2007 spring.
So, I shall post the results later.

Hi,

'memtest' is available on 'KNOPPIX', 'SystemRescueCD' and 'UBCD'.

I would let 'memtest' run through several passes, if possible overnight. If the fail comes up within a few test(s) then of course you should use that information.

These links and others can be found at 'Slackware-Links'. More than just Slackware® links!

Might want to query th hardware on your motherboard to verify the memory specs..
As you can see my System uses DDR 533 Mhz Memory and will accept a Maximum Capacity of 2GB of RAM.. if I try to put in more than that it will flake out as you are describing.

Thanks all

I put the 2 1G sticks back in and ran memtest, it bombs after 17% of the first pass (test 6
-33 errors) with "unexpected interrupt - Halting"
"Type Gen_Prot" and a whole load of Hex that must mean something to someone somewhere.

So next step, next step, try it with just 1 stick, and the first pass run's fine.

I hadn't heard of lshw, but installed that from disks and got

*-firmware
description: BIOS
vendor: Award Software International, Inc.
physical id: 0
version: 6.00 PG (07/15/2002)
size: 128KB
capacity: 192KB
capabilities: isa pci pnp apm upgrade shadowing escd cdboot bootselect socketedrom edd int13floppy360 int13floppy1200 int13floppy720 int13floppy2880 int5printscreen int9keyboard int14serial int17printer int10video acpi usb agp ls120boot zipboot biosbootspecification
*-cache:0
description: L1 cache
physical id: 8
slot: Internal Cache
size: 128KB
capabilities: synchronous internal write-back
*-cache:1
description: L2 cache
physical id: 9
slot: External Cache
size: 256KB
capacity: 2MB
capabilities: synchronous external write-back
*-memory
description: System Memory
physical id: 18
slot: System board or motherboard
size: 1GB
*-bank:0
description: DIMM
physical id: 0
slot: A0
size: 1GB
*-bank:1
description: DIMM [empty]
physical id: 1
slot: A1

No mention of capacity (as far as RAM is concerned).

I shall try swaping the 1G stick and try memtest again.

BIOS date of 2002.. is there a BIOS update available for your motherboard ?

Hi farslayer

Is 2002 really that ancient? (And I wouldn't have a clue about how to do a BIOS update either.)
At any rate, I am disabled and broke, so even getting the RAM upgrade was pushing the boat out for me.

Anyway, the story is, that one of the 1G memory sticks is well and truly unwell, the other one is fine. I have swapped stuff around physically (OK, I use an earthed copper pipe, the chasis, and whole bunches of tinfoil) but its done fine for all the two 256MB sticks several times, and the good 1G stick, so I don't reckon it's my fault.

But thanks for all the replies, and I now have heard of memtest and lshw, so I shall see if the shop will be good enough to replace the bad one tomorrow.

Hi,
For the BIOS update there are README/Howto for all the major BIOS manufactures. Just make sure to backup if the BIOS option is available, most do allow a backup.

Most reputable shops will go out of their way to assist you. Especially in these economic times. Good Luck!

Try running memtest with just stick "A" installed, then do it again with stick "B". Most likely the bad stick will quickly reveal itself, if one is actually defective.

From your description, I'd guess that while both sticks may be the same capacity, they run at different speeds, and RAM speed mismatches are notorious for creating instability. If you can post the specs of each RAM stick, that may be helpful