The primary limiting factor for running the FLUX.1 Dev model (12B parameters) on the AMD RX 7800 XT is the available VRAM. FLUX.1 Dev, especially for diffusion tasks, requires 24GB of VRAM when using FP16 (half-precision) for storing the model weights and intermediate activations during inference. The RX 7800 XT is equipped with 16GB of GDDR6 VRAM. This creates a VRAM deficit of 8GB, meaning the model cannot be loaded and executed in its entirety on the GPU without employing specific strategies to reduce memory footprint. The memory bandwidth of 0.62 TB/s is adequate, but irrelevant if the model cannot fit into memory. The absence of dedicated tensor cores on the RX 7800 XT suggests that it will rely on the GPU's shaders for matrix multiplication operations, which will impact the performance compared to GPUs with tensor cores.
Due to the VRAM limitation, running FLUX.1 Dev on the RX 7800 XT will require significant optimization. Model quantization is essential, consider using Q4 or even lower precision to reduce the VRAM footprint. Investigate using CPU offloading, where some model layers are processed on the CPU to free up GPU memory. However, this will significantly decrease performance. As an alternative, consider using a smaller model that fits within the 16GB VRAM or upgrading to a GPU with more VRAM. If CPU offloading is necessary, ensure you have sufficient system RAM and a fast CPU to mitigate performance bottlenecks.