The bandwidth of the PCIe interface is doubling rapidly every three years. Last month, the PCI-SIG completed version 0.5 of the PCIe 7.0 specification, and the official version 1.0 is expected to be released in 2025. With the significant increase in transmission speed, heat dissipation has also become a problem that has to be paid attention to.
Intel has been working on the PCIe interface overheating rate limiting driver for Linux since last year, and has recently released its fifth version. After the temperature exceeds the preset value, the driver can suppress the temperature rise by reducing the PCIe link speed, such as slowing down PCIe 5.0 to PCIe 4.0.
In addition to reducing link speeds, for PCIe 6.0 and PCIe 7.0, Intel also plans to reduce the PCIe link width (e.g., PCIe x4 to PCIe x2) to achieve speed limiting and temperature control.
PCIe itself supports energy-saving and cooling features such as ASPM, active state power management, and many GPUs will automatically reduce the speed and width of the PCIe link when idle to reduce standby power consumption. However, it seems that this is the first time that overheating has been performed from the host side, and it is unclear which part of the overheating event managed in the Intel driver refers to (PCIe controller?). PCIe physical interface? In any case, the heating problem of high-speed PCIe in the future should not be underestimated.