Well Kosmiq i will have to put down the fact ive been an Engineer for a long number of years, and know how things work.
It doesnt matter what Sisoft Sandra or any of these other programs say, they arent telling you in detail how the speed of the memory is fluctuating within a given time frame. All that they usually report is the speed located on the memory chips rom's.
There is good debugging software out there that can report the current speed of memory. Perhaps looking for those, and you will get a suprise