Actually, I disagree. It is not normal. The pumps are the same on each side. The difference is the radiator. The pumps on both side should sound the same. If you tilt you unit to the left and the sound goes away, its the pump. It's a known issue. Some will say live with it, it will diminish. I say for this kind of money, the pump should be silent, like most other pumps. I have used several types of pumps over the years, and none made this noise. At least send a message to corsair to document it.