Here's my two-cents worth. It is very important to stress-test your OC settings adequately.
Some people let MEMTEST86 run for 24 hours. The documentation for the program suggests that 3 passes on the default seven tests should catch anything, but I've seen errors pop up on the 5th iteration. I've let my test with the program go for 12 to 25 iterations.
For Prime95, it may be a very good stress test, but you need to run two instances of it simultaneously with a command-line parameter to achieve full 100% loading on a hyperthreaded Intel or dual core system. That's my understanding of it.
S&M -- a Russian stress-test by a fellow named "Serj" -- provides an ability to select the length of the test, whether you wish to test the CPU, the memory, or both, and the degree of loading. For instance, the program gauges "intensive gaming" at an 80% load. You can load up your machine to the limit, of course, and this would certainly find any errors. I usually back it off somewhat, but it is not only more adjustable than using PRIME95, it does a good job of monitoring temperatures and voltages, and it tests "VGA heating" during the CPU and power-supply tests.
I was able to get a more certain diagnosis of my memory problem -- isolating it to the memory module dual-channel kit -- with S&M. So I didn't have to fiddle with removal of modules to see if the errors went away. Of course, if you were interested in replacing one module, you might do that anyway. But this was a dual-channel kit under lifetime warranty.
With version 1.7.6, let the program finish loading and get a fix on your CPU speed. It is possible to generate false errors if you don't wait for it to do that.