Machine Check Exception on 2xAMD Opteron

ksool

Hey all,

I've just been working with a Tyan Thunder K8S Pro mobo with 2x AMD Opteron 248 and 4*2GB RAM. The machine will randomly lockup giving this error on the console

ksool · Posted: Tue Sep 18, 2007 12:38 am Post subject:

Here's the tail of mcelog:

SnEptUne · l33t Joined: 23 Aug 2004 Posts: 656

Yeah. Looks like memory problem. I don't know how realiable memtest is, since it didn't catch the problem with my RAM when my computer infrequently and randomly seg fault two years ago, even though I ran the test overnight.

But since your RAM has ECC, I suppose it is much easier finding error(s).
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dmpogo · Advocate Joined: 02 Sep 2004 Posts: 3468 Location: Canada

ksool · Posted: Tue Sep 18, 2007 1:53 am Post subject:

I might try and ship it back, but I doubt I'll have much luck on that front as I already sent it back for a busted bios and it's probably out of warranty by now.

Anyway, the problem only seems to occur once every couple of weeks, but that was when the machine was barely in use. I was hoping to use it as a backend for some thin X clients. Hopefully, given the rate of failure, it's only one of the sticks that's bad and the machine is still salvageable.

Does anybody know, once a stick has been deemed bad, is there anything you can do for it, or is it just trash? Might the logs give some insight into where the stick is bad and allow for that physical area to be blacklisted or something? It's not everyday a guy like me comes across a free server with 8GB ram and I'm not letting it go that easy.

dmpogo · Advocate Joined: 02 Sep 2004 Posts: 3468 Location: Canada

xbmodder · Guru Joined: 25 Feb 2004 Posts: 404

I'd ebay off the chips, and buy some new ones. They're cheap.
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ksool · Posted: Wed Sep 19, 2007 2:22 am Post subject:

Cheap? http://store.memory4less.net/36500132.html

Either way, I don't think I could rationalize buying any more ram for the machine. Assuming I had to chuck one stick, that box would still have 6x as much ram as the next runner up on my local network.

That kernel patch sounds super bad-ass. I'll have to look into it. The problem though, is that memtest86+ doesn't seem to catch the error every time, so I may be stuck running it for days just to find the bad sector.

Akkara · Posted: Wed Sep 19, 2007 2:48 am Post subject:

Sometimes the ram isn't outright bad, just a bit marginal on the timing, which only shows up when used on a heavily-loaded memory bus like the one you have.

If this is the problem, underclocking it 5 or 10% often fixes it. Increasing the RAS, CAS, etc. timings can also work, especially if it is just one timing that is close.

Alternatively, if you have another box with a 2GB stick in it, try swapping sticks. Chances are your old one will work in the less-loaded other box, and other one hopefully is better on the timing.