Computer stress.

I have two sets of ram. One set consists of two sticks, it is of identical brand model and buss speed and provides 1GB of memory per stick for a total of 2GB. The other set is of different model manufacturer and buss speed than the first set, but its two sticks, each providing 2GB per stick for a total of 4GB are identical to each other at least. I know in hardware gone by this may have caused a problem, but my motherboard proudly advertises its ability to take two such disparate sets of ram. They have worked together harmoniously for several months, but not it seems that set 1, the lower speed lower memory capacity older pair, were responsible for a series of blue screens that plagued me for the last three days or so. My computer appears to be running without interruption by cryptic blue screens and sudden resets on just the second set of ram, the lager and faster set.

But what should cause formerly good ram to go bad? By what mechanism does a little solid state miracle device with nothing even so crude and mechanical as power-leads to a fan suddenly break? Why would it work one day, be treated just as fine as it has in all of its days, but then not work. And on top of that windows's own memory diagnostics tool detects nothing wrong with this ram. Yet here I am, with the time to type all of this, something I haven't had in three days. Maybe I'm posting all of this too soon, and I'm simply on a record streak between bluescreens. If it continues much longer I may never trust a computer again. But if these past 15 minutes are indicative of a problem resolved, I will continue to worry over why such fine looking ram has just quit on me.