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Can I run this LLM?

Can a NVIDIA GB300 Grace Blackwell (288GB HBM + 480GB) run Mellum2.1 12B A2.5B Thinking (MoE)?

Mellum · Apache 2.0 · estimated for a 288.0 GB machine at 4K context.

Yes — it runs great.

Runs great

Best fit: Mellum2.1 12B A2.5B Thinking (MoE) at FP16 · 24.3 GB weights · 279–418 tok/s on a NVIDIA GB300 Grace Blackwell (288GB HBM + 480GB).

Pack & allocation notes: KV estimates assume a 1,024-token sliding window on 21 of 28 layers; actual runtime allocation may be higher. MXFP4_MOE is not listed. The FP16 label uses BF16 weights.

Arena Text Overall · style-controlled

UnratedNo exact match

No reviewed exact Arena match

No reviewed exact model/configuration match in the Arena Text Overall style-controlled snapshot. No family or editorial score is substituted. Local quantization quality is unmeasured.

Snapshot published 2026-10-08 · snapshot imported 2026-10-11 UTC · validated last-good data · manual refresh

Arena leaderboard dataset · Arena / lmarena-ai, Arena Leaderboard Dataset (CC BY 4.0). Selected Text Overall style-controlled rows; field names adapted, ratings unchanged. · dataset CC BY 4.0 · revision e16f90232986

Total memory at 4K context
25.2 GB
Weights + KV cache + runtime overhead
Estimated generation
279–418 tok/s
Estimated first token
~0.0s

Every quantization on this machine

On small screens, each quant lists every metric below its name. On wider screens, scroll sideways for total memory, speed and fit. Keyboard: focus the table, then use the arrow keys. Quant names stay visible.

Mellum2.1 12B A2.5B Thinking (MoE) quantizations on NVIDIA GB300 Grace Blackwell (288GB HBM + 480GB), estimated at 4K context. Weights and total memory are shown separately.
QuantWeightsTotal memorySpeedFit
Q4_K_M8.1 GB9.0 GB331–496 tok/sRuns great
Q6_K10.9 GB11.8 GB320–481 tok/sRuns great
Q8_012.9 GB13.8 GB313–470 tok/sRuns great
FP1624.3 GB25.2 GB279–418 tok/sRuns great

Ran Mellum2.1 12B A2.5B Thinking (MoE) on a NVIDIA GB300 Grace Blackwell (288GB HBM + 480GB)? Add your real numbers →