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View Full Version : Thousands of errors in Memtest86+ when loaded from specific hard drive, guess who?



Agent_24
06-01-2013, 06:16 PM
Here's a weird one....


Two days ago one of my machines crashed completely while running Linux. The machine has had no problems for months (maybe over a year) since I last had freezing that I fixed by cleaning and reseating the video card.

So, after rebooting I ran Memtest86+ and at first got a strange error about an 'unexpected interrupt' which I don't recall ever seeing before.
I turned it off and on again, tried Memtest again, and it progressed without issue until it got to test #7 where I started getting thousands of errors starting at 129MB.

I tried the RAM in another machine without problem. Uh-oh. So, I think, maybe the board or CPU is faulty...

Well, today I tried cleaning the RAM contacts, cleaning and reseating all the other cards and such (the system is quite old so bad contacts are not a bad theory I think) and yet still got the errors.


Well, time to check everything else first! I started disconnecting things... first I tried removing all USB devices, no good.

Then, I tried disconnecting hard drives (two IDE, two SATA) and booted Memtest86+ 4.20 (same version as before) from CD - at which point all the errors on test #7 were gone!

I thought I had narrowed it down to one of the IDE hard drives, an 80GB Seagate, because I only got errors with it plugged in, but I was fooling myself, because with it unplugged I HAD to use the CD.
I found that the problem only happens when actually loading Memtest from that drive.


Even with that drive plugged in, I could run Memtest from CD or another HDD and there are no errors on even a full pass including test #7.
Now, this 80GB drive IS the same drive that Linux was running from when the machine crashed.
This is also the same drive that Memtest seems to have problems loading from now (which it hasn't in the past)


So, I thought it seems that the HDD may be faulty, although I have not experienced any other problems with it, no SMART errors or anything

After driving myself mad for two days I decided to post here.. was just about to send when I decided to search on Memtest forums to see if anyone had similar errors before... well, would you believe it - it was all Memtest's fault!


http://forum.canardpc.com/threads/73508-Test-7-false-fail-RAM-ok-Maybe-solved.-Seems-to-be-a-ubuntu-problem
https://bugs.launchpad.net/ubuntu/+source/memtest86+/+bug/1071209

That 80GB drive is running Lubuntu 12.10 while the other drive has Xubuntu 12.04 and the CD of course is just the CD.


Well, I'm still none the wiser as to what caused the crash on Friday, but I'm pretty sure now it's not the RAM! (Ran proper versions of memtest for long enough today without errors)
Maybe a weird software issue or it was another problem caused by dirty contacts. Hopefully it was and my cleaning today got rid of it. We shall see...

What fun! :badpc:

feersumendjinn
06-01-2013, 11:51 PM
Try another PSU, had a similar problem with my brothers comp, went through most of what you did, lots of ram errors, found when PSU swapped for a new higher-wattage one, it all went away ( a clue may be that it ran clean when you disconnected those HDDs, less current drawn from the power supply unit (perhaps AC ripple getting through when under load)); the problem hasn't returned (still has original ram).

Agent_24
07-01-2013, 09:36 AM
It's a bug in memtest86+ in Ubuntu 12.10

Apparently it doesn't like being compiled with gcc-4.7

https://bugs.launchpad.net/ubuntu/+source/memtest86+/+bug/1071209