Llama-3.1 Nemotron Ultra 253B vs Seed 2.0 Pro

Llama-3.1 Nemotron Ultra 253B

NVIDIA

Llama-3.1-Nemotron-Ultra-253B-v1 is a 253-billion-parameter model from NVIDIA, derived from Meta's Llama 3.1 405B using neural architecture search (NAS) compression combined with NVIDIA's Nemotron post-training pipeline, which recovers and exceeds the base model's capability after structural compression. Released in April 2025, it supports toggling between a standard instruction mode and an extended reasoning mode via system prompt, allowing the same model to handle both rapid responses and deliberate chain-of-thought tasks. It is the flagship of the Nemotron family, available open-weight on HuggingFace and through NVIDIA NIM for enterprise inference.

ByteDance

Seed 2.0 Pro is ByteDance's flagship general-purpose model, released in February 2026 under the Doubao brand through the Volcengine API platform, developed by the company's Seed research team as a foundation for agentic applications requiring long-horizon reasoning and multimodal input comprehension. The model accepts text, images, and extended video — including hour-length recordings — targeting enterprise use cases in long-form document analysis, agentic coding (integrated with ByteDance's TRAE IDE), and multi-turn reasoning tasks. It anchors a three-tier product family alongside Seed 2.0 Lite and Mini, positioned as ByteDance's response to frontier model competition in the Chinese and global enterprise AI markets.