// RUN โ€” FITS

Can the Apple M4 Max 64GB run gpt-oss-20b?

Yes โ€” here's how fast and up to what context, with real measured numbers.

gpt-oss-20b on the Apple M4 Max 64GB

QuantFits?Max contextSpeedBeyond context
FP16 yes 54k 8.9-10.7 t/s ~0.2-0.2 (slow)
Q8 yes 134k 17.8-21.4 t/s ~0.3-0.4 (slow)
Q4 yes 169k 31.7-38.2 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 M4 Max 64GB run gpt-oss-20b?โ–ถ

Yes. At Q4 it generates ~31.7-38.2 tok/s and fits up to 169k context; beyond that it spills to SSD swap and slows to ~0.6-0.7 tok/s.

How much context fits?โ–ถ

At Q4, up to about 169k tokens stay in fast memory; longer context spills to SSD swap and throughput collapses.