Apple · apple

Apple M3 Ultra

Apple M3 Ultra has 256 GB of unified memory at 819 GB/s — about 178.56 GiB usable after driver and compositor overhead. 2108 of 2118 indexed models fit at 4K context with f16 KV. Note only 192 GB of its 256 GB is allocatable to the GPU.

Spec sheet· bandwidth, theoreticalFrom the file· fit from summed bytesPredicted· speed
Memory
256 GB
LPDDR5-6400
Bandwidth
819 GB/s
1024-bit bus
Tensor FP16
—
dense
TDP
—
Context4K8K16K32K64K128K
KV cachef16q8_0q4_0quantizing the KV cache is a ~2× lever on the dominant term at long context
vision language 192text 1812image 2audio tts 21audio asr 39video 16embedding 26

What fits at 4K context

largest quantization that fits, per model · 2108 of 2118 indexed
ModelBest quantParamsWeights●KV●Total in memory◐Headroom◐tok/s◐
MiniMax-M3MoEQ3_K_L427B190.89 GiB0.47 GiB191.93 GiB0.07 GiB20±37%
GLM-4.5MoEIQ4_NL358B189.74 GiB1.44 GiB191.77 GiB0.23 GiB17±37%
GLM-4.7MoEIQ4_NL358B189.62 GiB1.44 GiB191.65 GiB0.35 GiB17±37%
GLM-4.6-Derestricted-v3MoEIQ4_NL357B188.93 GiB1.44 GiB190.96 GiB1.04 GiB17±37%
GLM-4.6MoEIQ4_NL357B188.93 GiB1.44 GiB190.96 GiB1.04 GiB17±37%
GLM-5.1MoEIQ2_XXS754B189.92 GiB0.34 GiB190.87 GiB1.13 GiB20±37%
GLM-5MoEUD-IQ1_S754B189.71 GiB0.34 GiB190.65 GiB1.35 GiB20±37%
Qwen3-Coder-480B-A35B-InstructMoEUD-IQ3_XXS480B187.70 GiB0.97 GiB189.25 GiB2.75 GiB17±37%
openPangu-2.0-FlashMoEKV unresolvedBF16100B188.04 GiB0.20 GiB188.80 GiB3.20 GiB21±37%
cogito-671b-v2.1MoEUD-IQ1_M671B187.19 GiB0.27 GiB188.09 GiB3.91 GiB21±37%
DeepSeek-V3.1-TerminusMoEUD-IQ1_M685B187.19 GiB0.27 GiB188.08 GiB3.92 GiB21±37%
DeepSeek-V3-0324MoEUD-IQ1_M685B186.94 GiB0.27 GiB187.84 GiB4.16 GiB21±37%
cogito-v2-preview-deepseek-671B-MoEMoEUD-IQ1_M671B186.85 GiB0.27 GiB187.74 GiB4.26 GiB21±37%
DeepSeek-R1-0528MoEUD-IQ1_M685B186.69 GiB0.27 GiB187.59 GiB4.41 GiB21±37%
DeepSeek-TNG-R1T2-ChimeraMoEUD-IQ1_M685B186.69 GiB0.27 GiB187.59 GiB4.41 GiB21±37%
DeepSeek-Prover-V2-671BMoEUD-IQ1_M685B186.06 GiB0.27 GiB186.96 GiB5.04 GiB21±37%
DeepSeek-V3.2MoEUD-IQ1_M685B185.62 GiB0.27 GiB186.52 GiB5.48 GiB21±37%
Qwen3.5-397B-A17BMoEUD-IQ4_NL403B185.08 GiB0.12 GiB185.80 GiB6.20 GiB24±37%
Qwen3-Coder-REAP-363B-A35BMoEIQ4_XS363B183.56 GiB0.97 GiB185.11 GiB6.89 GiB16±37%
MiniMax-M2.7MoEQ6_K229B183.52 GiB0.97 GiB185.03 GiB6.97 GiB20±37%
Hermes-4-405BQ3_K_M406B181.96 GiB1.97 GiB184.76 GiB7.24 GiB4±8.3%
Hermes-3-Llama-3.1-405BQ3_K_M406B181.96 GiB1.97 GiB184.76 GiB7.24 GiB4±8.3%
r1-1776MoEIQ2_S671B183.47 GiB0.27 GiB184.36 GiB7.64 GiB21±37%
DeepSeek-R1MoEIQ2_S685B183.47 GiB0.27 GiB184.36 GiB7.64 GiB21±37%
Ornith-1.0-397BMoEUD-IQ4_NL397B182.60 GiB0.12 GiB183.32 GiB8.68 GiB24±37%
MiMo-V2.5MoEKV unresolvedQ4_1311B180.99 GiB0.47 GiB182.05 GiB9.95 GiB21±37%
NVIDIA-Nemotron-3-Ultra-550B-A55B-BF16MoEUD-IQ2_M561B180.64 GiB0.00 GiB181.23 GiB10.77 GiB20±37%
MiMo-V2-FlashMoEKV unresolvedQ4_1310B180.12 GiB0.47 GiB181.19 GiB10.81 GiB21±37%
Qwen3-235B-A22BMoEQ6_K235B179.80 GiB0.73 GiB181.12 GiB10.88 GiB16±37%
Qwen3-235B-A22B-Instruct-2507MoEQ6_K235B179.80 GiB0.73 GiB181.12 GiB10.88 GiB16±37%
Qwen3-235B-A22B-Thinking-2507MoEQ6_K235B179.80 GiB0.73 GiB181.12 GiB10.88 GiB16±37%
DeepSeek-Coder-V2-Instruct-0724MoEQ6_K236B180.25 GiB0.26 GiB181.10 GiB10.90 GiB20±37%
DeepSeek-V2.5MoEQ6_K236B180.25 GiB0.26 GiB181.10 GiB10.90 GiB20±37%
DeepSeek-Coder-V2-InstructMoEQ6_K236B180.25 GiB0.26 GiB181.10 GiB10.90 GiB20±37%
Qwen3-VL-235B-A22B-ThinkingMoEQ6_K236B179.76 GiB0.73 GiB181.08 GiB10.92 GiB16±37%
Qwen3-VL-235B-A22B-InstructMoEQ6_K236B179.76 GiB0.73 GiB181.08 GiB10.92 GiB16±37%
Qwen3-235B-A22B-abliteratedMoEI1-Q6_K235B179.76 GiB0.73 GiB181.08 GiB10.92 GiB16±37%
grok-2MoEQ5_K_M270B178.41 GiB1.00 GiB180.11 GiB11.89 GiB7±37%
DeepSeek-V3.1MoEUD-IQ1_S685B179.11 GiB0.27 GiB180.00 GiB12.00 GiB22±37%
GLM-4.6-REAP-268B-A32BMoEQ5_K_M269B177.71 GiB1.44 GiB179.74 GiB12.26 GiB16±37%
Llama-4-Maverick-17B-128E-InstructMoEKV unresolvedQ3_K_M402B177.95 GiB0.75 GiB179.27 GiB12.73 GiB27±37%
Trinity-Large-PreviewMoEQ3_K_M399B176.43 GiB0.94 GiB177.94 GiB14.06 GiB24±37%
command-a-plus-05-2026-bf16MoEQ6_K219B176.79 GiB0.50 GiB177.85 GiB14.15 GiB17±37%
Trinity-Large-TrueBaseMoEI1-Q3_K_M399B176.30 GiB0.94 GiB177.82 GiB14.18 GiB24±37%
Trinity-Large-ThinkingMoEIQ3_M399B176.24 GiB0.94 GiB177.76 GiB14.24 GiB24±37%
Nex-N2-ProMoEIQ3_M397B176.93 GiB0.12 GiB177.65 GiB14.35 GiB25±37%
Hy3MoEQ4_1299B174.90 GiB1.25 GiB176.73 GiB15.27 GiB19±37%
MiniMax-M2.1MoEQ6_K229B174.91 GiB0.97 GiB176.42 GiB15.58 GiB21±37%
MiniMax-M2MoEQ6_K229B174.91 GiB0.97 GiB176.42 GiB15.58 GiB21±37%
MiniMax-M2.5MoEQ6_K229B174.87 GiB0.97 GiB176.37 GiB15.63 GiB21±37%
MiniMax-M2.7-BF16-ultra-uncensored-hereticMoEQ6_K229B174.87 GiB0.97 GiB176.37 GiB15.63 GiB21±37%
ERNIE-4.5-300B-A47B-PTQ4_1300B174.57 GiB0.84 GiB176.08 GiB15.92 GiB4±8.3%
Qwen3.5-REAP-262B-A17BMoEQ5_K_M262B172.96 GiB0.12 GiB173.68 GiB18.32 GiB23±37%
Minimax-M3-abliterated-cleanMoEQ3_K_S427B171.06 GiB0.47 GiB172.10 GiB19.90 GiB22±37%
GLM-5.2MoEQ3_K_M753B169.33 GiB0.34 GiB170.27 GiB21.73 GiB22±37%
GLM-4.7-REAP-218B-A32BMoEQ6_K218B167.57 GiB1.44 GiB169.59 GiB22.41 GiB15±37%
Solar-Open2-250BMoEQ5_K_M250B165.65 GiB0.75 GiB166.97 GiB25.03 GiB24±37%
Step-3.7-FlashQ6_K_L201B160.20 GiB2.53 GiB163.31 GiB28.69 GiB4±8.3%
DeepSeek-V4-FlashMoEQ4_K291B153.33 GiB0.06 GiB153.99 GiB38.01 GiB27±37%
step-3.5-flashQ6_K199B150.81 GiB2.53 GiB153.92 GiB38.08 GiB4±8.3%
●From the file◐Predictedwhat these mean

Speed is modeled, not measured: decode is memory-bandwidth bound, so tokens per second is bytes read per token against achievable bandwidth. Mixture-of-experts models carry a wider band because only the routed experts are read each step, and few have been measured publicly.

Questions people ask

What AI models can a Apple M3 Ultra run?
2108 of 2118 indexed open-weight models fit a Apple M3 Ultra at 4,096 context with f16 KV cache, the largest being MiniMax-M3 at Q3_K_L. That covers text, vision-language, image, video and speech models.
How much usable memory does a Apple M3 Ultra actually have?
Its nameplate is 256 GB, but about 178.56 GiB is available to a model once driver and compositor overhead is accounted for, and only 192 GB of the pool can be allocated to the GPU at all.
Is a Apple M3 Ultra fast for local AI?
Its memory bandwidth is 819 GB/s, and that figure — not teraflops — is what governs token generation speed. Capacity decides what you can run; bandwidth decides how fast it runs.