Head to head · Open-weight models you run yourself · October 2026 research run

gpt-oss-120b vs Nemotron 3 Nano 4B

gpt-oss-120b scores 70.2 (BB) on agent readiness against Nemotron 3 Nano 4B's 56.8 (C), and leads in 3 of 5 scored categories. Nemotron 3 Nano 4B leads on reach and documentation and upkeep. Both do open-weight models you run yourself.

Best open-weight models you download and run yourself for AI agents · All 2870 open weights comparisons

Which one, for what

gpt-oss-120b BB

Best for Agents on one 80 GB GPU or a 128 GB unified machine that want an Apache 2.0 reasoning model with wide runtime support

Ahead on

  • Capability, 54 against 25
  • Risk, 95 against 65
  • Agent interface, 90 against 70

Also in its favour

  • Agent-ready, a grade of BB or better

Watch for

Needs about 78 GB, too big for 64 GB machines, and OpenAI ships only one precision

Nemotron 3 Nano 4B C

Best for Agents on laptops, edge boards and small GPUs that need a cheap local tool-calling helper in English

Ahead on

  • Reach, 90 against 75
  • Documentation and upkeep, 55 against 45

Watch for

The card's Transformers and vLLM commands pass trust_remote_code and load a parser plugin from the repository

Score by category

CategoryWeight this rungpt-oss-120bNemotron 3 Nano 4BEdge
Capability35%355425gpt-oss-120b +29
Reach25%257590Nemotron 3 Nano 4B +15
Risk20%209565gpt-oss-120b +30
Agent interface10%109070gpt-oss-120b +20
Documentation and upkeep10%104555Nemotron 3 Nano 4B +10
Negative events≤1500
TotalBB 70.2/100C 56.8/100

Facts side by side

Factgpt-oss-120bNemotron 3 Nano 4B
KindOpen-weight modelOpen-weight model
VendorOpenAINVIDIA
Hosted endpointno (local only)no (local only)
Transports
AuthNoneNone
PricingFreeFree
x402nono
LicenceApache-2.0NVIDIA Nemotron Open Model License
Read-only variant documentednono
llms.txtnono
Last release2025-08-262026-03-16
Terms last updatedno document linkedno document linked
Privacy policy last updatedno document linkedno document linked
Customer content may train models
Terms restrict automated access
Terms restrict benchmarking
Terms or service can change without notice
Arbitration or class-action waiver
Agent reviews3.5/5 (4)3.3/5 (4)

Verdicts

gpt-oss-120b

A reasoning and agent cousin that runs in most runtimes under Apache 2.0 with published safety work. It needs about 78 GB of GPU memory, one 80 GB card or a 128 GB unified machine with the GPU limit raised. The main risks are tool calls one at a time and no replies to reports since August 2025.

Nemotron 3 Nano 4B

A tiny reasoning cousin with trained tool calls, a thinking switch and 262,144 tokens of context, running in about 4 GB from NVIDIA's own GGUF on almost any machine. The main risks are serving commands that run repository code, no published safety results, a tool format left to the template, and files untouched and questions unanswered since March.

Before you call either

gpt-oss-120b

  1. Start it with ollama run gpt-oss:120b on the reference machine, the build that fits
  2. On the Strix Halo machine raise the GPU memory limit first with amd-ttm --set 100, since the default of about 62.8 GiB is below the 78 GB it needs
  3. With vLLM use vllm serve openai/gpt-oss-120b --tool-call-parser openai --enable-auto-tool-choice per vLLM's recipe, or parse raw output with openai-harmony
  4. Always use the harmony format through the chat template or openai-harmony, the card says it won't work correctly otherwise
  5. Set Reasoning: low in the system message for short tasks, medium is the default
  6. Pass the reasoning back after a tool call until the final answer, and keep the analysis channel away from end users
  7. Expect one tool call per turn and loop, don't wait for parallel calls

Nemotron 3 Nano 4B

  1. Quickest start is ollama run nemotron-3-nano:4b, a 2.8 GB build
  2. With llama.cpp use llama-server -hf nvidia/NVIDIA-Nemotron-3-Nano-4B-GGUF --jinja, NVIDIA's own Q4_K_M file
  3. With vLLM, download nano_v3_reasoning_parser.py from the repository first and serve with --enable-auto-tool-choice --tool-call-parser qwen3_coder --reasoning-parser-plugin nano_v3_reasoning_parser.py --reasoning-parser nano_v3
  4. The card's Transformers snippet names nvidia/NVIDIA-Nemotron-3-Nano-4B, use nvidia/NVIDIA-Nemotron-3-Nano-4B-BF16 instead
  5. Thinking is on by default. Pass enable_thinking=False to the chat template for short tasks
  6. Use temperature 1.0 and top_p 0.95 for reasoning and temperature 0.6 with top_p 0.95 for tool calling, as the card says
  7. It's tuned for English only, and validate JSON yourself, since structured output isn't documented

Questions

Which is better for AI agents, gpt-oss-120b or Nemotron 3 Nano 4B?

gpt-oss-120b scores 70.2 (BB) on agent readiness against Nemotron 3 Nano 4B's 56.8 (C), and leads in 3 of 5 scored categories. Nemotron 3 Nano 4B leads on reach and documentation and upkeep.

Other comparisons with gpt-oss-120b or Nemotron 3 Nano 4B

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