I don't waste time running memtest. If it can play games and run benchmarks, it is stable. Funny thing about memory is that when it's not stable, it is pretty obvious. As I stated before, the memory will to 250 per piece, just not when put together. Not sure if this is a mobo thing, or a memory thing. But I have always heard that a single stick of ram will overclock better than two sticks. Just like single sided memory will overclock better than double sided. And yes, I would not recommend Kinston memory for serious overclocking, but it is pretty cheap. I bought the memory to go with my NF7 and Barton 2500, so I am just using it on my new system until I decide on something better.