willitrun·ai

Can Qwen3.5 27B run on RTX 4080 Super 16GB?

YES — With Q3_K_S

D34Poor
Estimated from fit model

Qwen3.5 27B needs ~19.2 GB VRAM. RTX 4080 Super 16GB has 16.0 GB. With Q3_K_S quantization, expect ~22 tok/s.

Runtime: OllamaCapacity: OffloadBandwidth: MediumStack: BasicBottleneck: Host offload
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Operating mode

Choose the run profile you care about

Interactive favors responsiveness, while light API and scale-out lean harder on serving readiness. The fit stays the same, but the recommendation lens changes.

Current mode

Balanced

Balanced for general local use. Keeps the ranking neutral across personal and serving workflows.

Qwen3.5 27B at Q4_K_M needs 22.4 GB — too much for RTX 4080 Super 16GB (16.0 GB). Runs at Q3_K_S (19.2 GB) with low quality. 2 quantization levels fit.
Capabilities:

Select quantization to explore

Q4_K_M (Medium quality) 22.4 GB, exceeds 16.0 GB available
22.4 GB required16.0 GB available
140% VRAM needed

6.4 GB over capacity — needs offload or smaller quantization

Fit status

Too heavy

Decode

13.7 tok/s

TTFT

14177 ms

Safe context

4K

Memory

22.4 GB / 16.0 GB

Offload

30%

Memory breakdown

Weights16.5 GB
KV Cache3.2 GB
Runtime1.2 GB
Headroom1.6 GB

See how fast it feels

With memory offload — actual speed may be lower
See how fast it feelsQwen3.5 27B on RTX 4080 Super 16GB
1st promptCold start — includes initialization
>What is local AI inference?
Local AI inference means running an AI language model directly on your own hardware — your laptop, desktop, or server — instead of sending requests to a remote cloud API. When you run inference locally the model weights are loaded into your GPU or unified memory. Each token you generate requires reading those weights from memory, so memory bandwidth is the main bottleneck for decode speed. Key benefits of running locally: - Full privacy: your prompts never leave your machine - No per-token cost or rate limits - Works offline once the model is downloaded - Latency depends only on your hardware
2nd promptWarm — model ready, no init overhead
>How much VRAM do I need?
It depends on the model size and quantization level. A rough rule of thumb: Model size Q4 (4-bit) Q8 (8-bit) FP16 7B params ~4.3 GB ~7.5 GB ~14 GB 13B params ~7.9 GB ~13.9 GB ~26 GB 70B params ~42.7 GB ~74.9 GB ~140 GB Most people use 4-bit quantization (Q4_K_M) which gives 90-95% of full quality at a fraction of the memory. A 24 GB GPU can comfortably run most 7B-13B models.
Estimated: 13.7 tok/s decode · 14.2s TTFT (warm) · 34 tok/s prefill

What limits this setup

It fits through host-memory offload, and offload is the main reason performance drops.

CPU or host-memory offload is active

About 20% of the working set spills out of accelerator memory, which usually hurts latency and sustained decode throughput.

Very little memory headroom

You can run the model, but there is not much room left for longer context, bigger batches, extra apps, or future model updates.

Best improvement path

Remove offload with more accelerator memory

Prioritize a GPU or unified-memory tier that fits the whole model natively. Removing offload usually helps more than small compute gains.

Buy headroom, not only minimum fit

A slightly larger memory tier gives you safer context growth and makes the recommendation more future-proof.

Increase host RAM if you keep offloading

This setup may need roughly 2.2 GB of extra host RAM just for the offloaded portion, before OS and other tools.

Performance by workload

WorkloadGradeFitDecodeTTFTContext
ChatFToo heavy15.9 tok/s6629 ms4K
CodingFToo heavy13.7 tok/s14177 ms4K
Agentic CodingFToo heavy10.3 tok/s27222 ms4K
ReasoningFToo heavy13.7 tok/s16754 ms4K
RAGFToo heavy10.3 tok/s34027 ms4K

Inference speed

Qwen3.5 27B inference speed — tokens per second by GPU & Mac

Estimated decode speed (tokens/sec) for Qwen3.5 27B at Q4_K_M across popular GPUs and Apple Silicon, using the fastest local runtime per device. Fastest is RTX 5090 32GB at ~73 tok/s. Speed is memory-bandwidth bound, so cards that fit the whole model in VRAM run far faster than ones that offload to system RAM.

GPU / MacMemoryQuantSpeed (tok/s)Fits?
NVIDIARTX 5090 32GB
32 GBQ4_K_M72.9Fits
NVIDIARTX 4090 24GB
24 GBQ4_K_M46.5Offloads
RX 7900 XTX 24GB
24 GBQ4_K_M42.0Offloads
NVIDIARTX 3090 24GB
24 GBQ4_K_M39.8Offloads
Mac Studio M3 Ultra 256GB
256 GBQ4_K_M33.8Fits
MacBook Pro M4 Max 128GB
128 GBQ4_K_M33.4Fits
MacBook Pro M4 Max 64GB
64 GBQ4_K_M33.4Fits
Mac Studio M2 Ultra 128GB
128 GBQ4_K_M28.2Fits
Mac Studio M1 Ultra 128GB
128 GBQ4_K_M26.7Fits
MacBook Pro M4 Pro 48GB
48 GBQ4_K_M21.1Fits
MacBook Pro M3 Max 64GB
64 GBQ4_K_M14.6Fits
NVIDIARTX 4080 Super 16GB
16 GBQ4_K_M13.7Too big
MacBook Pro M1 Max 64GB
64 GBQ4_K_M13.4Fits
NVIDIARTX 4070 12GB
12 GBQ4_K_M4.8Too big
NVIDIARTX 3060 12GB
12 GBQ4_K_M3.0Too big
NVIDIARTX 4060 8GB
8 GBQ4_K_M2.0Too big

Estimates for single-stream decoding at Q4_K_M; real tokens/sec varies with prompt length, context, batch size, and runtime build. Prompt processing (prefill) is faster than the decode figures shown here.

Quantization options

How Qwen3.5 27B (27B params) fits at each quantization level on RTX 4080 Super 16GB (16.0 GB usable).

QuantBitsVRAMQualityFit
Q2_KBest for your GPU
2
10.5 GB
LowC51
Q3_K_S
3
13.2 GB
LowF0
NVFP4
4
15.1 GB
MediumF0
Q4_K_M
4
16.5 GB
MediumF0
Q5_K_M
5
19.4 GB
HighF0
Q6_K
6
22.1 GB
HighF0
Q8_0
8
28.9 GB
Very HighF0
F16
16
55.4 GB
MaximumF0

Get started

Copy-paste commands to run Qwen3.5 27B on your machine.

Run

docker run --rm -it ghcr.io/ggerganov/llama.cpp:full \ --hf-repo "unsloth/Qwen3.5-27B-GGUF" \ --hf-file "Qwen3.5-27B-GGUF-Q4_K_M.gguf" \ -c 4096 -ngl 99

Opciones de mejora

Hardware que ejecuta bien Qwen3.5 27B

Frequently asked questions

Can RTX 4080 Super 16GB run Qwen3.5 27B?

Yes, RTX 4080 Super 16GB can run Qwen3.5 27B at Q3_K_S quantization (Very compromised (needs ~2.2 GB host RAM)). The recommended Q4_K_M requires 22.4 GB which exceeds available memory, but at Q3_K_S it needs only 19.2 GB. Expected decode speed: 22.0 tok/s.

How much VRAM does Qwen3.5 27B need?

Qwen3.5 27B (27B parameters) requires approximately 22.4 GB at Q4_K_M quantization. On RTX 4080 Super 16GB, it fits at Q3_K_S using 19.2 GB.

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

The recommended quantization is Q4_K_M, but on RTX 4080 Super 16GB the best fitting quantization is Q3_K_S, which uses 19.2 GB.

What speed will Qwen3.5 27B run at on RTX 4080 Super 16GB?

On RTX 4080 Super 16GB, Qwen3.5 27B achieves approximately 22.0 tokens per second decode speed with a time-to-first-token of 8818ms using Q3_K_S quantization.

Can RTX 4080 Super 16GB run Qwen3.5 27B for coding?

For coding workloads, Qwen3.5 27B on RTX 4080 Super 16GB receives a F grade with 13.7 tok/s and 4K context.

What context window can Qwen3.5 27B use on RTX 4080 Super 16GB?

On RTX 4080 Super 16GB, Qwen3.5 27B can safely use up to 4K tokens of context at Q3_K_S quantization. The model's official context limit is —, but available memory constrains the safe maximum.

What should I upgrade first if Qwen3.5 27B feels slow on RTX 4080 Super 16GB?

Remove offload with more accelerator memory. Prioritize a GPU or unified-memory tier that fits the whole model natively. Removing offload usually helps more than small compute gains.

See all results for RTX 4080 Super 16GBSee all hardware for Qwen3.5 27B
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