// RUN โ€” FITS

Can the Apple M3 Max 128GB run GPT-J-6B?

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

GPT-J-6B on the Apple M3 Max 128GB

QuantFits?Max contextSpeedBeyond context
FP16 yes 775k 22.5-27.1 t/s ~0.6-0.7 (slow)
Q8 yes 821k 44.9-54.2 t/s ~1.1-1.4 (slow)
Q4 yes 842k 80.2-96.8 t/s ~2-2.4 (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 128GB run GPT-J-6B?โ–ถ

Yes. At Q4 it generates ~80.2-96.8 tok/s and fits up to 842k context; beyond that it spills to SSD swap and slows to ~2-2.4 tok/s.

How much context fits?โ–ถ

At Q4, up to about 842k tokens stay in fast memory; longer context spills to SSD swap and throughput collapses.