The case of a bad RAM chip and how I made friends with WinMemDiag

Well, my odd computer problems with large files finally became so frequent that I wanted to find the problem source, and not just guess.

The symptoms were these: when copying large files (200+ MB) from DVD to hard disk or from hard disk to USB drive, the almost constantly became corrupted.

However, for example .ZIP files have an internal CRC checksum, and on some occasions, large files were fine, and corrupted on other occasions.

I had long suspected my hard disk, but then I started doing plain-old file compares ("fc.exe /b" on the command line), and that revealed differencies in files, but every time at different addresses!

That made me think about my RAM (DIMM) chips, which I have four, at 512 MB each. I wanted to download a simple utility to test the chips, and to my surpirse I found that Microsoft has written one! It is named "Windows Memory Diagnostic" or "WinDiag" or "WinMemDiag". (Or just WMD, but that sounds scary.)

Now, this little utility proved to be a gem. It allows you to create book disk or a bootable CD-ROM (through an .ISO image), and once you boot your PC with the disk or CD, it starts to inspect your RAM.

It didn't take long until it find problems in one of my RAM chips, and it could even name in which bank it was in. Great tool!

I took that chip to my PC makes, and got a new one in exchange. It is the first time I've seen a Kingston memory chip fail, but I guess that can happen, too.

Best of all, now all my odd file corruptions disappeared. So my PC is humming again happily.