The good news is the memory ran flawlessly at it's rated speed and settings. The bad news is it only took 5MHz FSB over 275MHz before the system became unstable. I was still able to run some office aps, but gaming and benchmarking was out of the question at any voltage. However, the memory score at 275MHz FSB (550MHz DDR) is very impressive. If you are questioning CPU stability, don't. This CPU is known to hit as high as 290MHz FSB before becoming unstable. As for the motherboard, 275MHz to 280MHz FSB is about all she can do. We have been told that this memory has been known to overclock as high as 290MHz on certain ASUS motherboards, but that only with ASUS. I consider the DFI 875B to be one of the better motherboards on the market, so I'm comfortable in saying that most users will only see just what I did here; 275 to 280MHz FSB at a CPU ratio of 1:1. As to whether or not this is memory that could be used by hard core overclockers and gamers, I see no reason as to why not. After all, even hitting this memory's default of 550MHz is quite an accomplishment, even by the most experienced of Overclockers. Since there is no standard for PC4400, this is actually memory for overclocking. So to say this memory should only be used in moderate overclocking is pretty silly. As for "moderate gaming", you either game or you don't, and there isn't anything wrong with this RAM to keep you from gaming with the best of them.