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Voltarum Local LLM Hardware Guide

Best hardware to run gpt-oss-120b locally

gpt-oss-120b needs about 65 GB with a 32K context. These are the machines that hold it, from cheapest to fastest.

Editorial opinionReviewed Oct 11, 2026

OpenAI's open model ships with its experts in 4-bit, so it needs about 63 GB of weights in any quantisation, plus a small context cache. Only 5.1B parameters work per token, which makes it fast even on unified-memory machines. Anything with 96–128 GB of usable memory runs it well. See gpt-oss-120b for every option.

  1. #1 · Best value

    AMD Ryzen AI Max+ 395 (Strix Halo)

    Highly recommended
    Memory
    128 GB
    Bandwidth
    256 GB/s
    Power
    120 W
    Largest popular model at 4-bit
    Qwen3.5 122B A10B

    from $2,200 (typical price)

    Editorial opinionOverall 8.3/10

    128 GB in an x86 mini PC: the cheapest way to run it comfortably.

  2. #2 · Best overall

    Apple Mac Studio (M5 Max)

    Highly recommended
    Memory
    128 GB
    Bandwidth
    614 GB/s
    Power
    480 W
    Largest popular model at 4-bit
    Qwen3.5 122B A10B

    from $2,499 (launch price)

    Editorial opinionOverall 8.7/10

    614 GB/s makes it noticeably faster, and it is silent.

  3. NVIDIA GB10 Grace Blackwell (DGX Spark and partners)

    Photo: Daniel Lu (User:dllu) · CC BY-SA 4.0

    #3 · Best with CUDA

    NVIDIA GB10 Grace Blackwell (DGX Spark and partners)

    Recommended
    Memory
    128 GB
    Bandwidth
    273 GB/s
    Power
    240 W
    Largest popular model at 4-bit
    Qwen3.5 122B A10B

    from $5,000 (typical price)

    Editorial opinionOverall 7.6/10

    Same capacity class with the full NVIDIA stack.

  4. #4 · Fastest

    NVIDIA RTX PRO 6000 Blackwell

    For advanced users
    Memory
    96 GB
    Bandwidth
    1.79 TB/s
    Power
    600 W
    Largest popular model at 4-bit
    Qwen3.5 122B A10B

    from $8,565 (typical price)

    Editorial opinionOverall 8.4/10

    Fits entirely in 96 GB of GPU memory at 1.8 TB/s.

How we chose

  • Must hold the model with a 32K context in the memory the GPU can use by default.
  • Ordered by our overall assessment, weighing price, speed and ease of setup.

Read the methodology →