How much VRAM does Qwen3.5 27B need?

Qwen3.5 27B (27B parameters) requires approximately 23.9 GB of memory with Q4_K_M quantization.

What is the best quantization for Qwen3.5 27B?

The recommended quantization for Qwen3.5 27B is Q4_K_M, which balances quality and memory efficiency.

Can it run?

Yes, RTX 4000 Ada 20GB can run Qwen3.5 27B with a D grade (Very compromised). Expected decode speed: 13.6 tok/s.

DPoor

Very compromised

Using Q4_K_M in Ollama

Capabilities:

Fit status

Very compromised

Decode

13.6 tok/s

TTFT

14277 ms

Safe context

13K

Memory

23.9 GB / 20.0 GB

Offload

20%

Weights16.5 GB

KV Cache4.2 GB

Runtime1.2 GB

Headroom2.0 GB

Workload	Grade	Fit	Decode	TTFT	Context
Agentic Coding	F	Too heavy	17.0 tok/s	16517 ms	23K
Chat	D	Very compromised (needs ~1.3 GB host RAM)	15.9 tok/s	6656 ms	7K
Coding	D	Very compromised	13.6 tok/s	14277 ms	13K
RAG	F	Too heavy	17.0 tok/s	20646 ms	23K
Reasoning	D	Very compromised (needs ~2.7 GB host RAM)	14.7 tok/s	15575 ms

How Qwen3.5 27B (27B params) fits at each quantization level on RTX 4000 Ada 20GB (20.0 GB usable).

Quant	Bits	VRAM	Quality	Fit
Q2_K	2	10.5 GB	Low	C41
Q3_K_SBest for your GPU	3	13.2 GB	Low	C44

HuggingFace

huggingface-cli download hf-unsloth--qwen3-5-27b-gguf

Upgrade options

RX 7900 XTX 24GBBest value

C41.5 tok/s decode

~$999 MSRP

Mac mini M4 64GBBudget pick

C5.2 tok/s decode

~$1,099 MSRP

RTX 5090 32GBBiggest leap