It's well known that the more sticks of RAM you use, then you have the "potential" for a slightly degraded overclock. This is especially true if one stick is less stellar than the rest. Basically, RAM can only perform as good/fast as the worst/slowest module. If all 4 sticks test good and are fairly equal in performance, then you won't see much of a difference. I've used 4X256 of OCZ PC3500 in my IC7 and really noticed no difference in overclockability compared to 2X256. Only the hardcore that are pushing the max limits need to worry about this anyway.