Phoronix's end-of-2025 benchmarking on Linux 6.19 exposed severe hard hangs on AMD's newer RDNA3 and RDNA4 GPUs, halting tests across kernels 6.18 and 6.19—with no fixes from AMD or kernel logs for diagnosis. Building on prior coverage of performance boosts for legacy GCN GPUs now defaulting to AMDGPU, tests succeeded steadily on a wide range of older and mid-range hardware using Mesa 26.0-devel drivers.
Phoronix conducted extensive benchmarking to wrap up 2025, focusing on AMD Radeon graphics cards with the Linux 6.19 kernel. Plans for a comprehensive comparison expanded to include RDNA architectures, but testing stalled due to critical regressions in newer hardware.
Specifically, RDNA3 and RDNA4 GPUs encountered hard hangs during benchmarks on both Linux 6.18 and 6.19. These failures prevented remote system access and left no kernel logs, making diagnosis challenging. The author noted, "With these newer graphics cards on Linux 6.18/6.19 there would end up being hard hangs when running different benchmarks." Valve's Linux graphics team confirmed similar issues, highlighting the problem's severity.
No fixes have emerged from AMD, and the regression remains unbisectioned. The tester described it as "the most frustrating AMDGPU Linux issue I have encountered in years," easily triggered by GPU workloads and surprisingly present in Linus Torvalds' kernel tree.
Undeterred, the benchmarks proceeded with Linux 6.19 paired with Mesa 26.0-devel drivers, covering OpenGL, Vulkan graphics, Vulkan compute, and OpenCL via Rusticl. Tested models included the HD 7950, R9 285, R9 290, RX 590, RX Vega 56, RX 5500 XT, RX 5700, RX 5700 XT, RX 6600, RX 6600 XT, RX 6750 XT, RX 6800, RX 6800 XT, and RX 7600 XT. These provided a fresh performance snapshot for legacy and mid-range AMD hardware on the latest stack, offering insights into stability for users relying on established GPUs.
