Question 1

Can Mac Studio M2 Ultra 128GB run Qwen3.5 4B?

Accepted Answer

Yes, Mac Studio M2 Ultra 128GB can run Qwen3.5 4B with a C grade (Runs well). Expected decode speed: 213.1 tok/s.

Question 2

How much VRAM does Qwen3.5 4B need?

Accepted Answer

Qwen3.5 4B (4B parameters) requires approximately 18.3 GB of memory with Q4_K_M quantization.

Question 3

What is the best quantization for Qwen3.5 4B?

Accepted Answer

The recommended quantization for Qwen3.5 4B is Q4_K_M, which balances quality and memory efficiency.

Workload	Grade	Fit	Decode	TTFT	Context
Agentic Coding	C	Runs well	190.2 tok/s	1481 ms	158K
Chat	C	Runs well	190.2 tok/s	555 ms	40K
Coding	C	Runs well	213.1 tok/s	908 ms	81K
RAG	C	Runs well	190.2 tok/s	1851 ms	158K
Reasoning	C	Runs well	190.2 tok/s	1203 ms	81K

Quant	Bits	VRAM	Quality	Fit
Q2_K	2	1.6 GB	Low	D30
Q3_K_S	3	2.0 GB	Low	D30
NVFP4	4

Can Mac Studio M2 Ultra 128GB run Qwen3.5 4B?

Memory breakdown