Core i5 2500k weird overclock

Hi, I was overclocking my Core i5 2500K with my new Corsair H60 and a ASRock Extreme3 Gen3. I set the multiplier to 44 and BCLK to 100 (stock) because my temps were good there and I figured I wasn't going use more than that anyway. When I set it to 44, it kept going from 44, to 43, then back 44. I figured it was just a glitch, so I changed the multiplier to 43 and just started testing from that. It seemed to stay at 43 and I was happy. I came back to check it later, and it was bobbing between 42 and 43 now. Does anyone know why?