The Ryzen 7040 Series processor in Framework Laptop 16 is capable of operating at a sustained 45 W TDP (Thermal Design Power). To ensure optimal performance while keeping CPU temperature, touch temperatures, and fan noise to a minimum, we have developed an excellent thermal solution. The 45 watts of CPU power needs to be efficiently conducted into the vapor chamber, heatpipes, and fins, and carried away through airflow from the fans.
Due to the imperfect flatness of both the CPU die and the vapor chamber surface, a thermal interface material is necessary to fill in gaps and prevent insulative air from occupying that space. Traditionally, most computers use thermal grease, which contains thermally conductive particles suspended in silicone. While this method works reasonably well, the silicone itself is not particularly thermally conductive, and the paste can deteriorate or dry out over time, reducing its effectiveness.
Instead, in the case of the Framework Laptop 16, we have opted for a liquid metal thermal interface on the CPU. Liquid metal is a 100% metal sheet composed of indium, tin, and bismuth that transitions from solid to liquid at approximately 58 °C as the CPU heats up, completely filling any air gaps. Being a metal, it exhibits extremely high thermal conductivity, rated at 72 W/mK, which is significantly better than the typical 5-10 W/mK of traditional paste. Additionally, it does not dry out or deteriorate over time. We are utilizing Coollaboratory's Liquid MetalPad through their partner CCHUAN based in Taiwan.
You may be concerned about the safety of having a highly electrically conductive liquid inside a portable device. In this case, the answer is yes, as we have designed the thermal system to contain it at multiple levels. Firstly, we apply an insulative glue layer using a robotic fixture during Mainboard assembly to cover the small capacitors located directly next to the CPU dies. Secondly, an etched pattern on the surface of the vapor chamber holds the liquid metal in place through tension. Finally, a dual foam barrier surrounding the CPU is compressed between the processor package and the vapor chamber copper plate, preventing any liquid metal from escaping. All of these measures result in an efficient and effective thermal solution, ensuring excellent CPU performance.
