Radeon RX 9000 GPUs officially support UEFI systems only, AMD says

AMD’s latest Radeon RX 9000 series GPUs based on RDNA 4 architecture are optimized for UEFI BIOS only, the company has shared. Even though most systems are UEFI or Unified Extensible Firmware Interface-based, some older machines still run on Compatibility Support Module or CSM mode, which comes with a lot of limitations. Because of these limitations, the full potential of the Radeon RX 9000 series GPUs cannot be utilized.

AMD explains through a post on its support page that UEFI firmware provides critical functions to the PC and has overtaken the older, simpler standard called BIOS. These terms are, at times, used interchangeably. How this impacts the latest RX 9000 series graphics cards is that the older systems using legacy modes are CSM will not support the latest technologies such as Smart Access Memory (Resizable BAR) that enhance performance and efficiency.

This means only the systems with UEFI will be able to take full advantage of these technologies and deliver the optimal gaming experience when paired with the Radeon RX 9000 series GPUs. Furthermore, UEFI also enables features like support hard drives larger than 2.2TB, NVMe SSD boot support, faster startup, sleep, resume, and shutdown, and improved security, among others.

AMD recommends disabling CSM from the BIOS or UEFI menu. This is typically found under the Boot tab/menu. Of course, the steps will be a little different based on the motherboard manufacturer.

This does not mean that the Radeon RX 9000 series GPUs will not work with CSM or Legacy modes. They will still boot as normal and be able to run games, but the advertised performance and support cannot be ensured.