Solved Rebuilt PC with random BSOD occurrences

[Useless User]

Rastafari memory arrived this morning. I inserted it in the recommended DIMM-slots and started the PC without any issues - of course without ASUS' Optimal mode selected in the EZ-Setup screen for the time being (later, I want to run it at Optimal mode 3.8GHz although it would of course be nice to get the 4.2GHz back it was running on for nearly two years 24/7 (I do light simulations).

It is now running another round of prime95 with the temperature logged. Let's see what happens this time...

 

[Useless User]

Well, prime95 still soldiered on all day. So now, I try replicating the previous fail: 1. shut down 2. switch off the PSU 3. disconnect the power cord...

...which all worked. So, in the end - despite memtest86+ suggesting otherwise - it was the RAM or the DIMM slots on the fatherboard. But, still - how can RAM go bad by just switching a PC off for six months? I have never read anything regarding that.