TerEffic: Highly Efficient Ternary LLM Inference on FPGA

Abstract: Deploying LLMs efficiently on edge devices is often constrained by limited memory capacity and high power consumption. Low-bit quantization methods, particularly ternary quantization, have demonstrated significant potential in preserving model accuracy while substantially decreasing memory footprint and computational costs. However, existing general-purpose architectures and accelerators have not fully exploited the advantages of low-bit quantization due to insufficient specialized hardware support. We introduce TerEffic, an FPGA-based architecture tailored for ternary-quantized LLM inference. The proposed system offers flexibility through reconfigurable hardware to meet various system requirements. We evaluated two representative configurations: a fully on-chip design that stores all weights within on-chip memories, scaling out using multiple FPGAs, and an HBM-assisted design capable of accommodating larger models on a single FPGA board. Experimental results demonstrate significant performance and energy efficiency improvements. For single-batch inference on a 370 M-parameter model, our fully on-chip architecture achieves 16,300 tokens/second, delivering a throughput 192 times higher than NVIDIA Jetson Orin Nano with a power efficiency of 455 tokens/second/W, marking a 19-fold improvement. The HBM-assisted architecture processes 727 tokens/second for a larger 2.7B-parameter model, which is 3 times of the throughput of NVIDIA A100, while consuming only 46W, resulting in a power efficiency of 16 tokens/second/W, an 8-fold improvement over the A100.