Qwen3.5 4B DFlash — Hardware Requirements & GPU Compatibility
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Qwen3.5 4B DFlash is a 634M-parameter open language model from z-lab in the Qwen 3.5 family. It supports a context window of up to 262,144 tokens. At Q4_K_M it needs about 0.71 GB of VRAM — see which GPUs and Macs can run it below.
Runs great on a 24 GB GPU
Runs from 8 GB (Q4_K_M · 256K)Best on 24 GB (Q4_K_M · ~923 tok/s · 256K)Macs from 8 GB (Q4_K_M · ~101 tok/s)
Apache 2.0
Reference GPU · RTX 4090 24 GB
Estimates, ±20% · how we estimate
Run Qwen3.5 4B DFlash
One recommended way. Every other method, OS and quant is in the step-by-step guide.
Recommended
ollama run hf.co/AtomicChat/Qwen3.5-4B-DFlash-GGUFQ4_K_M fits fully on the RTX 4090 · 23.1 GB free · 16K context
Download: Qwen3.5-4B-DFlash-Q4_K_M.gguf0.38 GBAtomicChat
Other ways
each opens step-by-stepRun in cloud
Fits on RTX 3060 12GB (11 GB headroom) · Q4_K_M
- Generation speed
- ~330 tok/s
- generation speed
- Cost per 1M output tokens
- $0.070
- per 1M output tokens
How Much VRAM Does Qwen3.5 4B DFlash Need?
Select a quantization level; the listed hardware adheres to it.
| Quantization | VRAM | +32K | On RTX 4090 (reference) | |
|---|---|---|---|---|
| 0.6 GB | 1.1 GB | 2-bit · K-quant — 2-bit quantization with K-quant improvements | Fits: 256K context · ~1092 tok/s | |
| 0.6 GB | 1.1 GB | 3-bit medium — 3-bit medium quantization | Fits: 256K context · ~1024 tok/s | |
| 0.7 GB | 1.2 GB | 4-bit medium — 4-bit medium quantization — most popular sweet spot | Fits: 256K context · ~923 tok/s | |
| 0.8 GB | 1.3 GB | 5-bit medium — 5-bit medium quantization — good quality/size tradeoff | Fits: 256K context · ~840 tok/s | |
| 0.8 GB | 1.3 GB | 6-bit, very good — 6-bit quantization, very good quality | Fits: 256K context · ~771 tok/s | |
| 1.0 GB | 1.4 GB | 8-bit, near-lossless — 8-bit quantization, near-lossless | Fits: 256K context · ~676 tok/s | |
| 1.6 GB | 2.1 GB | 16-bit · bfloat — Brain floating point 16 — preferred for training | Fits: 256K context · ~410 tok/s |
Selected Q4_K_M
4-bit medium quantization0.9GBat 16K context
- Weights
- 0.4 GB
- KV cache
- 0.3 GB
- Overhead
- 0.3 GB
Fits RTX 4090 (reference) · 23.1 GB free · ~923 tok/s
≥50 tok/s needs ≥55 GB/s · RTX 5090 ~1641, RTX 3090 Ti ~923
Which Hardware Can Run Qwen3.5 4B DFlash?
Q4_K_M · 0.7 GBQwen3.5 4B DFlash (Q4_K_M) requires 0.7 GB of VRAM to load the model weights. For comfortable inference with headroom for KV cache and system overhead, 1+ GB is recommended. Using the full 262K context window can add up to 4.0 GB, bringing total usage to 4.7 GB. 52 GPUs can run it, including NVIDIA GeForce RTX 5090, NVIDIA GeForce RTX 3090 Ti. 163 devices with unified memory can run Qwen3.5 4B DFlash, including Mac Studio (M3 Ultra, 256GB), Mac Studio (M3 Ultra, 512GB).
≤ 11 GB
≤ 11 GB tier →fits · 7.1 GB free · up to 256K ctx
16 GPUs · 1 Mac class · 2 device families
RTX 3080~696Simulate output on RTX 3080RTX 2080 Ti~564Simulate output on RTX 2080 TiRTX 3070 Ti~557Simulate output on RTX 3070 TiM3*8 GB~101Simulate output on iMac 24" M3 (8 GB)Orin Nano~93Simulate output on NVIDIA Jetson Orin Nano 8GB (Super)iPhone~67Simulate output on iPhone 1720 GB
fits · 19.1 GB free · up to 256K ctx
1 GPU
RX 7900 XT~676Simulate output on RX 7900 XT32–40 GB
fits · 31.1 GB free · up to 256K ctx
1 GPU · 3 Mac classes · 4 device families
RTX 5090~1641Simulate output on RTX 5090M5 Max36 GB~454Simulate output on Mac Studio M5 Max (36 GB)M532 GB~151Simulate output on MacBook Air 13" M5 (32 GB)Orin~188Simulate output on NVIDIA Jetson AGX Orin 32GBSnapdragon X Elite (X1E-80-100)~124Simulate output on Snapdragon X Elite Copilot+ PC
By VRAM tier · typical GPUs and Macs at Q4_K_M
Alternatives to Qwen3.5 4B DFlash
Qwen 3.5 family · 34 models →Similar models
3| Model | Score | VRAM | tok/s | Why it is similar |
|---|---|---|---|---|
| T5gemma B B Ul2 ITGoogle | — | 2.5 GB | ~504 | same size |
| Qwen3 0.6B BaseAlibaba | — | 1.6 GB | ~840 | same size |
| Qwen1.5 0.5B ChatAlibaba | — | 2.3 GB | ~753 | same size |
Specifications
- Publisher
- z-lab
- Family
- Qwen 3.5
- Parameters
- 634M
- Architecture
- DFlashDraftModel
- Context Length
- 262,144 tokens
- Vocabulary Size
- 248,320
- Release Date
- 2026-03-05
- License
- Apache 2.0
Frequently Asked Questions
How much VRAM does Qwen3.5 4B DFlash need?
Qwen3.5 4B DFlash requires 0.7 GB of VRAM at Q4_K_M, or 1.6 GB at BF16. Full 262K context adds up to 4.0 GB (4.7 GB total).
VRAM = Weights + KV Cache + Overhead
Weights = 634M × 4.8 bits ÷ 8 = 0.4 GB
KV Cache + Overhead ≈ 0.3 GB (at 2K context + ~0.3 GB framework)
Fit ratings and hardware model lists check this model with room for a 16K-token context, which needs a little more memory.
KV Cache + Overhead ≈ 4.3 GB (at full 262K context)
VRAM usage by quantization
What's the best quantization for Qwen3.5 4B DFlash?
For Qwen3.5 4B DFlash, Q4_K_M (0.7 GB) offers the best balance of quality and VRAM usage. Q5_K_M (0.8 GB) provides better quality if you have the VRAM. The smallest option is Q2_K at 0.6 GB.
VRAM requirement by quantization
★ Recommended — best balance of quality and VRAM usage.
Can I run Qwen3.5 4B DFlash on a Mac?
Yes — MacBook Air 13" M3 (8 GB) and 145 other Macs can run Qwen3.5 4B DFlash. Apple Silicon uses unified memory, so the model shares RAM with the system. At Q4_K_M you need at least 0.7 GB of usable unified memory (RAM minus macOS overhead).
Can I run Qwen3.5 4B DFlash locally?
Yes — Qwen3.5 4B DFlash can run locally on consumer hardware. Popular tools include Ollama, LM Studio, and llama.cpp.
How fast is Qwen3.5 4B DFlash?
At Q4_K_M, Qwen3.5 4B DFlash can reach ~6761 tok/s on AMD Instinct MI350X. On NVIDIA GeForce RTX 4090: ~923 tok/s. Speed depends mainly on GPU memory bandwidth. Real-world results typically within ±20%.
tok/s = (bandwidth GB/s ÷ model GB) × efficiency
Example: NVIDIA B200 → 8000 ÷ 0.71 × 0.65 = ~7324 tok/s
Estimated speed at Q4_K_M (0.7 GB)
Real-world results typically within ±20%. Speed depends on batch size, quantization kernel, and software stack.
What's the download size of Qwen3.5 4B DFlash?
At Q4_K_M, the download is about 0.38 GB. The full-precision BF16 version is 1.27 GB. The smallest option (Q2_K) is 0.27 GB.
Which GPUs can run Qwen3.5 4B DFlash?
52 consumer GPUs can run Qwen3.5 4B DFlash at Q4_K_M. Top options include AMD Radeon RX 6700 XT, AMD Radeon RX 6800, AMD Radeon RX 6800 XT. 52 GPUs have plenty of headroom for comfortable inference.
Which devices can run Qwen3.5 4B DFlash?
163 devices with unified memory can run Qwen3.5 4B DFlash at Q4_K_M (0.7 GB), including AMD Ryzen AI 9 HX 370 (Strix Point) Laptop, ASUS Ascent GX10, Beelink GTR9 Pro (Ryzen AI Max+ 395, 128 GB), Framework Desktop (Ryzen AI Max+ 395, 128 GB). Apple Silicon Macs use unified memory shared between CPU and GPU, making them well-suited for local LLM inference.