We recently put together a custom build computer for a client – getting the best quality components possible for the budget by meticulously reviewing all component choices.

After putting the hardware together, we set about installing Windows 7 Professional 64bit only to run into some odd behaviour – Blue screens of death and video corruption.

We removed the additional graphics card and half of the memory – a 16gb set of Corsair Vengeance DDR3, which allowed us to install the operating system successfully.  After running some initial experiments with the memory, we ended up with 12gb of the 16gb purchased – convinced that the removed memory module was faulty.  However, later when downloading large files from the internet, we found that they were being mysteriously corrupted.  Windows was running fine and there were no other symptoms.

So we again scrutinised the memory closer, running the computer on 1 of the memory modules in turn,  this time copying a 4GB file from an external USB drive to the 1TB hard disk (D) and running WinMD5 Free – Windows MD5 Utility Freeware to generate an MD5 hash of the file. The file was then copied to the SDD drive (C) and the MD5 recalculated on the copied file. This process was repeated 3 times for each memory module.

Amazingly, one memory module produced a different MD5 hash consistently.  When the file was being copied between drives, it was being buffered in the available memory where it was being corrupted.  It’s amazing that there are no warnings or checks in place.  So if you are in doubt about memory or corruption of files, try the simple process above.