Can I run gpt-oss-120b on a 12GB card?

No. No published quantization of gpt-oss-120b fits a 12GB card at any context with q8_0 KV cache.

How much VRAM does gpt-oss-120b need?

Its published quantizations range from 58.27 GiB to 60.88 GiB in weights alone, before KV cache and runtime overhead.

Does gpt-oss-120b fit in 12GB of VRAM?

Not at these settings. No indexed quantization of gpt-oss-120b fits 12GB card at any context we compute, with q8_0 KV. The smallest shipped quantization is 58.27 GiB in weights alone, against 11.16 GiB usable. CPU offload can still run it, slowly.

From the file· weights summed from filesFrom the file· KV computed per layerPredicted· speed and compute buffer

KV cache dtypef16 q8_0 q4_0— 12 GB card, 11.16 GiB usable after overhead

Every quantization at every context

total memory required; green fits, red does not

Quant	Weights●	4K◐	8K◐	16K◐	32K◐	64K◐	128K◐
F16	60.88 GiB	61.8	61.8	62.0	62.3	62.9	64.1
Q8_0	59.03 GiB	59.9	60.0	60.1	60.4	61.0	62.2
MXFP4	59.03 GiB	59.9	60.0	60.1	60.4	61.0	62.2
Q6_K	58.94 GiB	59.8	59.9	60.0	60.3	60.9	62.1
Q5_K_M	58.57 GiB	59.4	59.5	59.7	60.0	60.6	61.8
Q5_K_S	58.56 GiB	59.4	59.5	59.7	60.0	60.6	61.8
Q2_K_L	58.54 GiB	59.4	59.5	59.6	59.9	60.5	61.7
Q4_K_M	58.46 GiB	59.3	59.4	59.6	59.9	60.5	61.7
Q4_K_S	58.45 GiB	59.3	59.4	59.6	59.8	60.4	61.6
Q4_1	58.41 GiB	59.3	59.4	59.5	59.8	60.4	61.6
Q3_K_M	58.33 GiB	59.2	59.3	59.4	59.7	60.3	61.5
Q4_0	58.32 GiB	59.2	59.3	59.4	59.7	60.3	61.5
Q2_K	58.27 GiB	59.2	59.2	59.4	59.7	60.3	61.5
Q3_K_S	58.27 GiB	59.1	59.2	59.4	59.7	60.3	61.5

●From the file◐Predictedwhat these mean

Figures are GiB of total memory: weights plus KV cache plus compute buffer and backend overhead. Weights and KV are near-exact; the overhead term is modeled. Hover any cell for the breakdown.

Why there are no speeds on this page

A capacity is not a card. Whether a model fits depends only on memory, so every figure above holds for any 12GB accelerator. How fast it runs depends on memory bandwidth, which varies several-fold between cards of the same capacity — so putting a tokens-per-second number here would be inventing one. Pick a specific card from hardware and the speed column appears.

Why other calculators disagree

A parameters × bits ÷ 8 estimate ignores two things that dominate at long context. First, the weights themselves are not the nominal rate — quantizations are mixtures, so the real file is consistently larger than the label implies. Second, most of this model's layers cache only a 128-token window rather than the full context.