In this article we're going to concentrate on why and how memory goes bad and what causes memory problems.
If you've ever worked on a PC and all of a sudden in the middle of blasting the heck out of some space invader your PC goes black and then suddenly reboots look no further than some kind of memory problem. This does not necessarily mean that the memory chip in your computer has gone bad, though that is always a possibility. But it does point to some kind of problem.
The least serious of these problems are actually caused not by the memory itself but by the applications the user happens to be running at the time. The sad truth is, some applications are just poorly written and have a tendency to overwrite memory locations outside of the area the program itself was running in. When this happens many times the memory locations overwritten just happen to be where the operating system is running and that's what causes your computer to reboot. If you suspect that one of your programs is the culprit you can try reinstalling it and then if that doesn't work you'll probably have to discontinue using it and find something to replace it.
Sometimes though the problem is with the memory chip or chips themselves. Chips go bad. That is just a fact of life. But the reasons for a chip going bad can be one of many.
One of the main reasons for memory failure is the power supply of the computer. A PC uses a switching power supply to convert 120Vac to the voltages that are required by your PC. The problem with power supplies is that the voltage coming from your wall is far from perfect. If you have a defective power supply, or one that is just plain cheap, what happens is your power supply may fail to filter out the noise that can mess up your computer system. Most often this type of problem shows up as a parity error in your memory chips. So while it may appear that the chip itself is bad the real problem is with the power supply. So replacing the memory chip itself won't do any good because the chip itself isn't the problem.
Sometimes the problem is with the design of the motherboard. Because of the various types of SIMM motherboard manufacturers try to accommodate them all which is just not possible. By doing this they invite problems that could have been avoided by just focusing on a few SIMM and designating which SIMM will work with their board. Of course this will result in fewer sales so there is no way this is going to happen. Another problem is one that is similar to the power supply problem where the motherboard is unable to filter out enough noise and again this will cause a parity error.
Finally, chips sometimes just go bad for a number of reasons such as excessive heat, movement or even just putting the chip in wrong and breaking or bending a pin. Oddly, bad chips occur less frequently than the other problems mentioned.
So if you're working on your PC and it goes black or you get yourself a windows memory error or blue screen of death, check your power supply and motherboard first. More likely than not you'll find the problem in one of those two places.
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Michael Russell
Your Independent guide to Computer Memory
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