How much VRAM does Qwen3.5 4B need?

Qwen3.5 4B (4B parameters) requires approximately 6.8 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, RTX 3090 24GB can run Qwen3.5 4B with a C grade (Runs well). Expected decode speed: 276.2 tok/s.

CUsable

Runs well

Using Q4_K_M in Ollama

Capabilities:

Fit status

Runs well

Decode

276.2 tok/s

TTFT

701 ms

Safe context

56K

Memory

6.8 GB / 24.0 GB

Weights2.4 GB

KV Cache0.8 GB

Runtime1.2 GB

Headroom2.4 GB

Workload	Grade	Fit	Decode	TTFT	Context
Agentic Coding	C	Runs well	268.5 tok/s	1049 ms	105K
Chat	C	Runs well	268.5 tok/s	393 ms	28K
Coding	C	Runs well	276.2 tok/s	701 ms	56K
RAG	C	Runs well	268.5 tok/s	1311 ms	105K
Reasoning	C	Runs well	268.5 tok/s	852 ms	56K

How Qwen3.5 4B (4B params) fits at each quantization level on RTX 3090 24GB (24.0 GB usable).

Quant	Bits	VRAM	Quality	Fit
Q2_K	2	1.6 GB	Low	D31
Q3_K_S	3	2.0 GB	Low	D31
NVFP4	4

Upgrade options

MacBook Pro M4 Max 36GBBudget pick

C105.9 tok/s decode

~$2,499 MSRP