I have a Memorex 512MB DDR PC3200 stick of RAM that is causing parity errors on my server. I have moved the stick to another slot, and the errors re-emerged. So, its the DIMM itself causing the problem; not the onboard slot. Now, I have replacement DIMMs which are Crucial 512MB DDR PC3200 sticks. I replaced one of the Crucial sticks with the bad Memorex and rebooted the server and it came back with another parity error on the same DIMM which I just replaced. I had to replace the adjacent 512 stick on the other module to clear the errors. I don't understand why the Crucial stick didn't work and why I had to replace the other DIMM on the opposite module. Any ideas??

Could have been timing errors with one stick having lower than the other so the lowest was being used causing the error for the new stick which only works at the higher timing also some memory just does not like being mixed with other brands/modules of different sizes .. all kinds of things like this will cause the errors hardware issues can be a mysterious thing at imes.