Uiler Posted August 18, 2003 Report Share Posted August 18, 2003 Something very very strange is happening with my computer. First of all it has been playing up for the last few weeks. I thought at first it was a dying hard drive because the symptoms seemed to be that of a dying hard drive (I noted them in a previous thread - basically tons of bad blocks, continuous very bad file system corruption etc). However I replaced my hard drive and whilst the first replacement reported bad blocks, the second replacement did not report bad blocks. Yet the same problems were occuring! Tons of Signal 11 crashes, file system corruptions etc. I finally figured out that it only seemed to be occuring when I rebooted. If I could get it working at all, it would usually be stable for ages and ages until I rebooted. One of my friends then suggested that it could be bad RAM that was syncing badly with the data on my hard drive when I rebooted. So I used memtest86 to check my RAM. Bingo - >60 errors. OK, so time to check which RAM module is "bad". I checked the 2nd and 3rd slots. Tons of errors. I put the 1st module back in and took out the 3rd one. Tons of errors. Took out the 2nd one. Yeah! No errors. So I figured the 2nd module was bad. I put the 3rd module in the 2nd RAM slot. Passed memtest86 with flying colours. Then I put the 2nd RAM module in the 3rd RAM slot and...that also passed memtest86 with flying colours. Huh? The only thing different from my previous unstable >60 memory errors configuration was that I had placed the RAM module that was in the 2nd slot in the 3rd slot, and the RAM module that was in the 3rd slot into the 2nd slot. How on earth could that possibly have fixed the problem? My system is much more stable now (touch on wood). At least it hasn't been dying every reboot (I've must have rebooted it half a dozen times just to check) and I ran memtest86 again on all 3 modules and it passed. I guess that I could be putting the "bad" module on a higher bank so it is accessed less, therefore making my system more stable, but that wouldn't explain why it is now passing the memtest86 tests where before it was showing > 60 errors. I am truly confused. I checked memtest86's documentation and it says that all swapping memory modules should do if one is bad, is give you RAM errors at different pages. Quote Link to comment Share on other sites More sharing options...
aRTee Posted August 18, 2003 Report Share Posted August 18, 2003 Hardware can be like that, who knows your memstick was just not connected as well as it should have been. My office colleague is working on RF stuff, doing lab measurements of their chip design (gsm rf chip), something went wrong with one of the measurement sockets they use to test the chips, and it had to be resoldered,... And bingo, all impedances are different. Can you imagine, in a socket, where you don't even solder stuff, but just plug things in, that it may happen that the thing is just not properly seated? Maybe some dust, a tiny string of cotton fibre or so just making the connection 'just about not entirely good enough'.... So I can imagine this happens. It used to be a remedy also in the older days, for some isa cards they would say: if it seems to be faulty, just rock it a bit in the slot, pull it out and put it back in.... So your story doesn't surprise me that much, maybe only in the sense that this doesn't happen more often. BTW had a similar problem with my tvcard once, took it out, put it back in the same slot, then it worked again.... Quote Link to comment Share on other sites More sharing options...
mtweidmann Posted August 18, 2003 Report Share Posted August 18, 2003 As your problem went away when you moved things around i would guess it was something to do with the physical contacts. It could be that the RAM was not sitting in the slot properly or had dirty conatcts. By removing it and replacing it several times you managed to get a better contact. Or the RAM could be slightly mis-formed, something that matters in one slot but not in another. As your system now works quite happily I'd just leave it alone. Quote Link to comment Share on other sites More sharing options...
Ixthusdan Posted August 18, 2003 Report Share Posted August 18, 2003 This is not an uncommon hardware problem. Before any hardware is disposed of, I always "re-seat" whatever I'm working with in its slot, including processors. The quick connects are convenient, but it is also too easy to have poor connections! Quote Link to comment Share on other sites More sharing options...
Glitz Posted August 18, 2003 Report Share Posted August 18, 2003 Yes, it is also a good idea when you install memory to rock the module forward and backward gently (a few millimeters only) until it is seated properly. You know that it is seated when it stops making crackling noises when you wiggle it (fingers popping into position). Glitz. PS. If you look at the gold contacts on the memory module and see dirt you can clean it simply by taking a pencil eraser and gently rubbing the contacts. Quote Link to comment Share on other sites More sharing options...
pmpatrick Posted August 18, 2003 Report Share Posted August 18, 2003 Agree with all of the above re the seating of the ram. If these erratic problems come up again, you may also want to look at your power supply. A PSU running out of spec can cause ram to malfunction in very erratic ways. Quote Link to comment Share on other sites More sharing options...
kmack Posted August 19, 2003 Report Share Posted August 19, 2003 A common problem with RAM is different metals in the card and the socket connections. (i.e. one is gold plated, the other is steel only) Some problems of corrosion can be caused by dissimilar metals like this, and may require cleaning every 12 months or so depending on humidity and ambient temps. You may not see much sign of corrosion without a very close examination, but it is enough to disrupt the signal and cause problems. The pencil eraser cleaning idea is good, just don't leave the eraser dust on the connector when you plug it back in! :) Quote Link to comment Share on other sites More sharing options...
ral Posted August 19, 2003 Report Share Posted August 19, 2003 If you dimms are different brands, the order does make a difference. Dont know why, but have had similar problems before and changing the order fixed it. Quote Link to comment Share on other sites More sharing options...
tyme Posted August 19, 2003 Report Share Posted August 19, 2003 I think it has to do with certain types of memory not liking other types (for varying reasons) but if you put the one that dislikes the other first, it won't even know that other one is there. but if it's second to the one it doesn't like, it can cause conflicts. i know, very untechnical explanation....but you get the point ;-) Quote Link to comment Share on other sites More sharing options...
Ixthusdan Posted August 19, 2003 Report Share Posted August 19, 2003 It is the board and the ram, not the ram itself. Some boards have a narrow tolerance for ram performance. If you put the good ram in the first position, the cheap ram will work! If you flip it around, all the ram acts erratically. It's the board. Quote Link to comment Share on other sites More sharing options...
tyme Posted August 19, 2003 Report Share Posted August 19, 2003 you're right Ix :-) Quote Link to comment Share on other sites More sharing options...
ral Posted August 19, 2003 Report Share Posted August 19, 2003 Good enough for me. Someoen told me to try it... it worked fine, Never bothered to check why :) Quote Link to comment Share on other sites More sharing options...
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