is this in windows, if so look at you cpu multiplier, sometimes it will drop from ex. a 16 to a 4
but if thats not so
and to fix it, in your overclocking menu, goto dram frequency and open up the dropdown menu and pick a higher frequency
yes im running windows my cpu multiplier is at 17.4 i belieave and when i go into my oc menu to clock my ram back to its original speed... i don't last in windows too long(system crashed after a min. aprox)