From the question and answer you provided there is no easy way to know what really is going on. The only thing I could think of was that there is a bug when the generic drivers pass a particular command to the CPU. When running at the higher speed (which means higher heat/different event timings) one of the transistors in the CPU could have switched wrong, causing the whole thing to crash.
Running at a lower speed can have a subtle affect on the interaction between the installation environment and the CPU. This subtle change prevents the error from happening and allows you to install the OS. Once you get into windows, completely different code is in use and additional drivers are loaded that are optimized for your hardware. This combination of drivers prevents the bug from surfacing and you are able to operate normally.
Does this mean your hardware is bad? No.
Is this something to be worried about? Most likely not.
Is this just a theory? Yes.
I could be totally wrong, but based off of what I know about CPU's it's the only thing that makes sense. I'm not a chip designer, but I know that computers are incredibly complex and behavior like this is almost impossible to reproduce on different hardware.
Hope that helps.
