How much VRAM does Qwen3.5 4B need?

Qwen3.5 4B (4B parameters) requires approximately 12.4 GB of memory with Q4_K_M quantization.

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

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

Can it run?

Yes, NVIDIA H100 80GB can run Qwen3.5 4B with a C grade (Runs well). Expected decode speed: 988.5 tok/s.

CUsable

Runs well

Using Q4_K_M in Ollama

Capabilities:

Fit status

Runs well

Decode

988.5 tok/s

TTFT

350 ms

Safe context

103K

Memory

12.4 GB / 80.0 GB

Weights2.4 GB

KV Cache0.8 GB

Runtime1.2 GB

Headroom8.0 GB

Workload	Grade	Fit	Decode	TTFT	Context
Agentic Coding	C	Runs well	1153.3 tok/s	350 ms	199K
Chat	C	Runs well	1153.3 tok/s	350 ms	51K
Coding	C	Runs well	988.5 tok/s	350 ms	103K
RAG	C	Runs well	1153.3 tok/s	350 ms	199K
Reasoning	C	Runs well	1153.3 tok/s	350 ms	103K

How Qwen3.5 4B (4B params) fits at each quantization level on NVIDIA H100 80GB (80.0 GB usable).

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

Upgrade options

MacBook Pro M3 Max 128GBBudget pick

C98.4 tok/s decode

~$2,499 MSRP

Mac Studio M1 Ultra 128GBBest value

C180.3 tok/s decode

~$3,999 MSRP