In message <422703D9.1080200@aol.com>, Peter Hufnagel writes:

>
>Anyways, on to figuring out why any memory in
>the 2nd 512M fails, but works in the first 512M.
>

I had a similar problem with a laptop once -- both cards were fine 
individually, but if they were both installed together, I got memory 
errors.  Nor was it a a system board problem.

I was told that the problem was memory bus capacitance -- or or both 
DIMMs were slightly out of spec; together, that caused a problem.

But if it's always the second 512M that's failing, another possibility 
is that your system board is bad, though it may just be dirty contacts.

		--Prof. Steven M. Bellovin, http://www.cs.columbia.edu/~smb