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I have a rather old motherboard with 4 DDR2 slots, all occupied.
I bought the board, RAM modules, and CPU from an acquaintance, second hand, so I do not know the exact history of the problem.
The problem is:
On rare occasions, the machine fails to boot. i.e. When I press the power button:
- I see no display at all
- The CPU fan runs, stops, runs.. repeatedly with the same frequency.
- The Speaker does not make the usual on-boot 'beep'
When I asked the original owner about this problem, he asked me to 'pull out the RAM modules and switch their slots'.
I was sceptical about this solution, but I tried it, and the machine booted.
Since then, whenever this occurs, I have found a cause-effect relationship between 'switching the modules' and 'the machine succeeding in booting'.
My question is: Why does switching the modules (temporarily) fix the failure to boot? It does not seem logical. I guess the answer would also need to explain why this can happen in the first place.
If it matters: The modules sit flush in the slots (they are pushed in properly). They are Corsair XMS2 modules of 1GB each, the heatsinks are thick enough that they (almost) touch each other when on the board.
@BonGart What about if it is a new motherboard and new ram and you have tried several different sets of ram? – Soenhay – 2017-09-01T22:30:32.050
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Have you ever tested the Ram? Like... with http://www.memtest86.com
– Bon Gart – 2012-05-09T15:50:47.497@BonGart - +1. This is good advice. No I haven't. I will try it, at some point. Although, I don't see that will help me understand why switching modules works. – ArjunShankar – 2012-05-09T15:56:23.480
1Because one of the modules might not be working, regardless of what slot you put it in. I remember a windows box I had with one (of 4) bad sticks. I was able to install Windows without error with that stick in the system, but I only saw issues when I transferred large files (got CRC errors). As far as corrosion is concerned, you can use a pencil eraser to clean the contacts on the Ram itself. If the Ram goes into the slots easily, it might be that they are too lose. It might even be that you only need to wiggle them. But checking to see if any are bad is still a step. – Bon Gart – 2012-05-09T16:04:47.717
@BonGart - Yes, you could be right about the bad module. I will definitely test the modules. – ArjunShankar – 2012-05-09T16:09:33.777