Even though my memory tests alright with memtest and Hyper PI, I still don't ignore the fact it could very well be faulty in some way. Perhaps it's an error so small that only in very specific conditions it causes a system crash.
I'm considering buying some other RAM modules and see if this changes anything. My only concern is that, if my RAM is not the issue, I could be introducing yet another variable prone to errors, given that memory is the most sensitive component in any computer when it comes to stability, in my experience.
If I go that route, I have the second issue of getting appropriate modules. Here in South America, I don't have the luxury if being picky about what brand of memory to chose from. Geil, Kingstom and Corsair are the most abundant brands available, but their respective top notch models are quite expensive and I would really hate to expend so much money on something that could not fix my issue. I have found at a trusted store some g.skill ram, however I've been reading lately at the g.skill forums that users have been having problems with their rams and Asus mobos even though the modules are listed in the QVLists.
I don't know if I will run the full test tonight or some other day, but let's see what comes up this time around.