This Prime95 debate is really getting old.. I think someone should make a sticky about it so newcomers and experts as well can have some common ground. In the end, everything is subjective so if someone doesn't think Prime95 is important and s/he has no problem with daily use of the system, that is "stable". How many machines "in the world" would stress the CPUs 100%, or even 10% all the time? Most office systems are probably idling 80% of the time and the other 20% of the time the CPU utilization is probably 5~10%. For them, Prime95 is meaningless.
Now, if we talk about a render farm or servers, or even a personal computer while intensive gaming or encoding, etc. then the stability becomes something. Remember, any components or even software can cause a system crash. It doesn't necessarily a stressed CPU that's responsible for a system instability. Now, in this community, we're hardware enthusiasts and in order to communicate, we need a sort of agreement which we discuss things upon. Prime95 has been used for such a long time, and became a de-facto standard for stability testing for CPUs. If an individual disagrees and again, s/he has no problem with his machine even though the machine doesn't pass Prime95 for 10 mins, then it's probably fine by her/him. And we shouldn't judge(?) her/his machine. Also it's a well known fact that often times Prime stable is not equalt to 3D stable. Also, while you're Priming your system, someone comes in from outside and turn your house heat up to 85F, and your system which was doinng Prime for 24 hours fails, then is that machine not stable?
The essence of my argument is this: If someone doesn't feel the need/importance of Prime95, then it's fine by itself. However, when you come to the public (a community like AT) and want to brag about your OC'ing and the stability of your rig, be prepared to be asked "Where is the dual-Prime95 shot?" Prime95 has acquired its status as stability test through many, many years by many, many people, and it indeed has co-relation with a system's stability. You can be satisfied by yourself while playing your favorite game with a sky-high OC'ing, but without Prime95 or something in that sort, it ends there and you should still be content by it.
If you can play your games and do whatever you want without Prime95 test, then what's the problem? But the thing is, we're not interested in what game you play and how much you're enjoying the specific game with your overclocked rig. Some might not like the game you play, some might not have a similar setup as yours. So here comes the Prime95 as a stability test. And it's a damn good one for that.
Prime95 as a common ground, a starting point for discussion. That's the point. Without that communication is impossible. If you're happy with your OC without Prime95, then that's it. You're happy. But once you come out(!) and say "Look at my supadupamegaultraeatmyass OC!", then be prepared to hear "Show us the Prime"!