Arctic Silver 5 does not contain any silicone. The suspension fluid is a proprietary mixture of advanced polysynthetic oils that work together to provide three distinctive functional phases. As it comes from the syringe, Arctic Silver 5's consistency is engineered for easy application. During the CPU's initial use, the compound thins out to enhance the filling of the microscopic valleys and ensure the best physical contact between the heatsink and the CPU core. Then the compound thickens slightly over the next 50 to 200 hours of use to its final consistency designed for long-term stability.