Nicehash CPU usage

[x_acidburn_x]

So long story short, I had some hardware issues this weekend and had to switch a rig from Hive OS to Win7 with nicehash. Hive OS uses very little CPU power but Nicehash is starting off about 6% then jumping to 80% after about 10 minutes with CPU mining turned off. Odd part is the second I move the mouse the CPU usage drops back down to 6%. I'm using a Core i5 2400. Any thoughts?