Apple Mac Studio M3 Ultra
$5,299 — discontinued
The unified-memory bandwidth king. The M3 Ultra runs at 819 GB/s — roughly 3× any Strix Halo or GB10 box — and at launch scaled to 512GB, enough to run DeepSeek R1 671B at 4-bit entirely in memory (~17–18 tok/s, under 200W). The catch as of September 2026: the 256GB and 512GB configs were pulled during the DRAM shortage, 96GB was the last config Apple sold, and Apple has now retired the M3 Ultra for the M5 Ultra — so this is a secondary-market buy. No CUDA — MLX/llama.cpp only.
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Specifications
| Chip | Apple M3 Ultra (28-core CPU / 60-core GPU, up to 32/80) |
| Neural Engine | 32-core |
| Unified Memory | 96GB (256/512GB configs discontinued 2026) |
| Memory Bandwidth | 819 GB/s |
| Storage | 1TB – 16TB SSD |
| Networking | 10GbE |
| I/O | 6× Thunderbolt 5, HDMI 2.1, SDXC |
Pros
- 819 GB/s — the highest-bandwidth unified-memory desktop you can buy
- At launch, 512GB ran DeepSeek R1 671B Q4 in memory under 200W, silent
- Thunderbolt 5 + macOS MLX-optimized stack
Cons
- No CUDA — MLX / llama.cpp only; many AI tools assume NVIDIA
- Retired by Apple in September 2026 (M5 Ultra replaced it) — secondary market only
- Slow prefill/prompt-processing on long contexts vs GPU rigs
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