Cambricon-GS: An Accelerator for 3D Gaussian Splatting Training With Gaussian-Pixel Hybrid Parallelism

3D Gaussian Splatting (3DGS) is a breakthrough in 3D reconstruction using 3D Gaussians. However, even on highend GPUs like the NVIDIA A100, reconstructing complex scenes remains time-consuming, taking over 15 minutes. The main bottleneck is α-computation, which accounts for 71.25 % of training workload, yet 93.03 % of it is invalid due to the localized influence of Gaussians. To address this issue, we propose Cambricon-GS, an accelerator for 3DGS training with Gaussian-Pixel hybrid parallelism. At the software level, we introduce a hybrid parallel workflow that breaks the limitation of conventional pixel-only parallelism through two key techniques: Center-Pixel Gaussian Culling (CPGC), which eliminates invalid Gaussians early, and SeedDriven Gaussian Region Exploration (SDGRE), which reduces invalid computation for partially valid Gaussians by selectively exploring valid regions. Overall, the workflow significantly reduces α computations, lowering the workload to 17.99 %. At the hardware level, Cambricon-GS decouples α-computation and α blending into GUnits and PUnits, organized in a 2D mesh-based NoC that supports asynchronous execution and efficient data routing. We further boost performance via Gaussian/Pixel load balancing and tiled SSIM based pipelining. The evaluation results show that Cambricon-GS achieves 19.63×, 14.86×, 15.42×, 2.98× and 2.63× speedup, and 78.62×, 63.00×, 61.72×, 3.89× and 3.22× energy saving, compared to A100, GSCore, GBU, GSArch, and GauSPU, respectively, with negligible image quality loss.