At the start of August Jason Clinton from Advanced Clustering Technologies Inc. posted a link to the “Breakin” tool that they created (and open sourced) for hardware stress-tests and diagnostics. He wrote:

We have a tool on our website called “breakin” that is Linux 2.6.25.9 patched with K8 and K10f Opteron EDAC reporting facilities. It can usually find and identify failed RAM in fifteen minutes (two hours at most). The EDAC patches to the kernel aren’t that great about naming the correct memory rank, though.

If you read the website though you’ll find it does a lot more than that, which is pretty cool. Be aware that it does use the Intel and AMD closed source maths libraries though if you’re sensitive to non-free software.