🔌
New: connect Claude & other AIs to GenAIList over MCP — research the catalog and contribute to the shared knowledge base. Learn how →
// RUN — FITS
Can the Apple M3 Max 48GB run NeMO Megatron GPT 20B?
Yes — here's how fast and up to what context, with real measured numbers.
NeMO Megatron GPT 20B on the Apple M3 Max 48GB
| Quant | Fits? | Max context | Speed | Beyond context |
|---|---|---|---|---|
| FP16 | yes | 6k | 6.8-8.2 t/s | ~0.2-0.2 (slow) |
| Q8 | yes | 83k | 13.6-16.4 t/s | ~0.3-0.4 (slow) |
| Q4 | yes | 116k | 24.3-29.3 t/s | ~0.6-0.7 (slow) |
Estimate (memory-bound). Beyond "max context" the KV cache spills to SSD swap and speed drops to the "beyond" figure.
FAQ
Can the Apple M3 Max 48GB run NeMO Megatron GPT 20B?▶
Yes. At Q4 it generates ~24.3-29.3 tok/s and fits up to 116k context; beyond that it spills to SSD swap and slows to ~0.6-0.7 tok/s.
How much context fits?▶
At Q4, up to about 116k tokens stay in fast memory; longer context spills to SSD swap and throughput collapses.