readygpu

Mac Studio M3 Ultra 256GB vs NVIDIA DGX Spark 128GB

For running models locally, priced in the UK. At 8k context the first runs 80 models fully in memory, the second 76.

In short

The Mac Studio M3 Ultra 256GB has more memory for models: 256 GB against 128 GB. At 8k context the Mac Studio M3 Ultra 256GB runs 80 of the models we track fully in memory and the NVIDIA DGX Spark 128GB 76; only the Mac Studio M3 Ultra 256GB holds MiniMax M2. On the models both run fully in memory, the Mac Studio M3 Ultra 256GB is about 3.1× as fast as the NVIDIA DGX Spark 128GB (estimated, median across models). In the UK the Mac Studio M3 Ultra 256GB costs £8,499 at eBay (used) and the NVIDIA DGX Spark 128GB £5,499 at Amazon: the NVIDIA DGX Spark 128GB is £3,000 cheaper.

Updated . Speeds are estimates; how they are worked out.

Mac Studio M3 Ultra 256GB

£7,499

eBay

Add to build
NVIDIA DGX Spark 128GB

£5,499

Amazon

Add to build

Specifications

SpecMac Studio M3 Ultra 256GBNVIDIA DGX Spark 128GB
ChipApple M3 Ultra (80-core GPU)GB10 Grace Blackwell
Memory bus1024-bit256-bit
Memory bandwidth819 GB/s273 GB/s
FP16 compute28 TFLOPS62 TFLOPS
SoftwareMetalCUDA
Unified memory256 GB128 GB
GPU can use by default192 GB119 GB
GPU can use, tuned248 GB122 GB
Operating systemmacosdgx-os
ProcessorM3 Ultra 32-core20-core Arm (GB10)
Storage2000 GB4000 GB

What each runs

Estimated decode speed with the most precise quant that fits each one est.

ModelMac Studio M3 Ultra 256GBNVIDIA DGX Spark 128GB
DeepSeek V4 Flash27tok/sMXFP414tok/sUD-Q2_K_XL
GLM 5.3 Flash20tok/sUD-Q4_K_XL12tok/sUD-Q2_K_XL
Qwen 3.8 Flash Next5tok/sQ8_03tok/sQ4_K_M
MiniMax M2.728tok/sQ6_K15tok/sUD-Q3_K_M
Qwen 3.8 27B18tok/sQ8_06tok/sQ8_0
Qwen 3.5 122B-A10B30tok/sQ8_012tok/sQ6_K
Qwen 3.6 27B18tok/sQ8_06tok/sQ8_0
gpt-oss 120B93tok/sMXFP430tok/sMXFP4
Qwen3 Coder Next73tok/sQ8_023tok/sQ8_0
Nemotron 3 Super 120B-A12B25tok/sQ8_09tok/sUD-Q6_K
Gemma 4 31B16tok/sQ8_05tok/sQ8_0
Mistral Small 4 119B42tok/sQ8_013tok/sQ8_0
Qwen 3.6 35B-A3B97tok/sQ8_031tok/sQ8_0
Qwen 3.5 27B18tok/sQ8_06tok/sQ8_0
Gemma 4 26B-A4B70tok/sQ8_022tok/sQ8_0
GLM 4.5 Air16tok/sQ8_05tok/sQ8_0
Qwen 3.5 35B-A3B97tok/sQ8_031tok/sQ8_0
Qwen3 Next 80B-A3B94tok/sQ8_030tok/sQ8_0
GLM 4.7 Flash56tok/sQ8_018tok/sQ8_0
Devstral Small 2 24B20tok/sQ8_06tok/sQ8_0
Nemotron 3.5 Lightning 30B-A3B93tok/sUD-Q6_K_XL30tok/sUD-Q6_K_XL
gpt-oss 20B121tok/sMXFP439tok/sMXFP4
Kimi Linear 48B-A3B97tok/sQ8_031tok/sQ8_0
Qwen3 Coder 30B-A3B80tok/sQ8_025tok/sQ8_0
Qwen3 32B14tok/sQ8_05tok/sQ8_0
Gemma 4 12B41tok/sQ8_013tok/sQ8_0
Qwen 3.5 9B54tok/sQ8_017tok/sQ8_0
Mistral Small 3.2 24B20tok/sQ8_06tok/sQ8_0
Gemma 3 27B18tok/sQ8_06tok/sQ8_0
DeepSeek R1 Distill Qwen 32B14tok/sQ8_05tok/sQ8_0
Llama 3.3 70B7tok/sQ8_02tok/sQ8_0
Ministral 3 14B34tok/sQ8_011tok/sQ8_0
Qwen3 14B31tok/sQ8_010tok/sQ8_0
DeepSeek R1 0528 Qwen3 8B54tok/sQ8_017tok/sQ8_0
Qwen3 8B54tok/sQ8_017tok/sQ8_0
Phi-4 14B31tok/sQ8_010tok/sQ8_0
Qwen 3.5 4B111tok/sQ8_035tok/sQ8_0
Ministral 3 8B52tok/sQ8_017tok/sQ8_0
Granite 4.2 8B50tok/sQ8_016tok/sQ8_0
Gemma 4 E4B63tok/sQ8_020tok/sQ8_0
LFM2.5 8B-A1B218tok/sQ8_069tok/sQ8_0
Llama 3.1 8B69tok/sQ6_K22tok/sQ6_K
Qwen2.5 0.5B843tok/sQ8_0268tok/sQ8_0
Qwen3.5 0.8B572tok/sQ8_0182tok/sQ8_0
Qwen3.5 2B342tok/sQ5_K_M109tok/sQ5_K_M
DeepSeek R1 Distill Qwen 1.5B250tok/sQ8_080tok/sQ8_0
MiniCPM5 2B176tok/sQ8_056tok/sQ8_0
LFM2.5 2.6B158tok/sQ8_050tok/sQ8_0
LFM2.5 VL 3B158tok/sQ8_050tok/sQ8_0
Spark X2.5 4B157tok/smlx-4bit50tok/smlx-4bit
granite vision 4.1 4b124tok/sQ8_039tok/sQ8_0
granite 4.2 3b117tok/sQ8_037tok/sQ8_0
LFM2.5 24B A2B114tok/sQ8_036tok/sQ8_0
Mellum2.1 12B A2.5B Thinking113tok/sQ8_036tok/sQ8_0
Kimi VL A3B Thinking 250695tok/sQ8_030tok/sQ8_0
Kimi VL A3B91tok/smlx-8bit29tok/smlx-8bit
DeepSeek R1 Distill Qwen 7B62tok/sQ8_020tok/sQ8_0
GLM 4 9B 041462tok/smlx-5bit20tok/smlx-5bit
DeepSeek R1 Distill Llama 8B55tok/sQ8_018tok/sQ8_0
Ministral 3 8B Reasoning 251252tok/sQ8_017tok/sQ8_0
GLM 4.6V Flash52tok/sQ8_016tok/sQ8_0
GLM 4.1V 9B Thinking44tok/smlx-8bit14tok/smlx-8bit
DeepSeek R1 Distill Qwen 14B31tok/sQ8_010tok/sQ8_0
MiniMax M229tok/sQ6_Kwon't run
MiniMax M2.129tok/sQ6_Kwon't run
MiniMax M2.529tok/sQ6_K13tok/sMXFP4
Qwen3.8 27B OBLITERATED25tok/smlx-4bit8tok/smlx-4bit
Devstral Small 250720tok/sQ8_06tok/sQ8_0
Magistral Small 250620tok/sQ8_06tok/sQ8_0
Magistral Small 250720tok/sQ8_06tok/sQ8_0
Magistral Small 250920tok/sQ8_06tok/sQ8_0
GLM 4.5V19tok/sQ8_06tok/sQ8_0
GLM 4.6V19tok/sQ8_06tok/sQ8_0
DeepSeek V4 Flash 073118tok/sMXFP4won't run
DeepSeek V4 Flash Vision Exp17tok/sMXFP4won't run
granite 4.2 30b16tok/sQ8_05tok/sQ8_0
DeepSeek R1 Distill Llama 70B7tok/sQ8_02tok/sQ8_0
Kimi Dev 72B7tok/sQ8_02tok/sQ8_0
Devstral 2 123B Instruct 25124tok/sQ8_02tok/sQ6_K
Mistral Medium 3.5 128B4tok/sQ8_02tok/sQ6_K
DeepSeek R1won't runwon't run
DeepSeek R1 0528won't runwon't run
DeepSeek R1 Zerowon't runwon't run
DeepSeek V3 0324won't runwon't run
DeepSeek V3.1won't runwon't run
DeepSeek V3.1 Terminuswon't runwon't run
DeepSeek V3.2won't runwon't run
GLM 4.6won't runwon't run
GLM 4.7won't runwon't run
GLM 5.1won't runwon't run
GLM 5.2won't runwon't run
GLM 5.3won't runwon't run
Kimi K2won't runwon't run
Kimi K2 Instruct 0905won't runwon't run
Kimi K2 Thinkingwon't runwon't run
Kimi K2.5won't runwon't run
MiniMax M3won't runwon't run

Questions

Which is better for local AI, the Mac Studio M3 Ultra 256GB or the NVIDIA DGX Spark 128GB?
Choose the Mac Studio M3 Ultra 256GB to run bigger models. Choose the Mac Studio M3 Ultra 256GB for speed. Choose the NVIDIA DGX Spark 128GB to spend less.
Which can run bigger models, the Mac Studio M3 Ultra 256GB or the NVIDIA DGX Spark 128GB?
At 8k context the Mac Studio M3 Ultra 256GB runs 80 of the models we track fully in memory and the NVIDIA DGX Spark 128GB 76; only the Mac Studio M3 Ultra 256GB holds MiniMax M2.
Which is faster for local AI, the Mac Studio M3 Ultra 256GB or the NVIDIA DGX Spark 128GB?
On the models both run fully in memory, the Mac Studio M3 Ultra 256GB is about 3.1× as fast as the NVIDIA DGX Spark 128GB (estimated, median across models).
What is the price difference between the Mac Studio M3 Ultra 256GB and the NVIDIA DGX Spark 128GB?
In the UK the Mac Studio M3 Ultra 256GB costs £8,499 at eBay (used) and the NVIDIA DGX Spark 128GB £5,499 at Amazon: the NVIDIA DGX Spark 128GB is £3,000 cheaper.

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