Qwen3.5 4B: VRAM requirements & speed
Qwen3.5 4B (4.66B dense, apache-2.0). Native context 256k, 1.01M with YaRN. Smallest GGUF: 2.74 GB.
Memory needed by quantization and context
GGUF file size plus f16 KV cache (and fixed overhead of ~1 GB per GPU not shown). Source: unsloth/Qwen3.5-4B-GGUF.
| Quant | File | +8k ctx | +32k ctx | +128k ctx | +256k ctx | +1M ctx |
|---|---|---|---|---|---|---|
| Q4_K_M | 2.74 GB | 3.1 GB | 3.9 GB | 7.1 GB | 11.4 GB | 35.6 GB |
| Q5_K_M | 3.14 GB | 3.5 GB | 4.3 GB | 7.5 GB | 11.8 GB | 36.0 GB |
| Q6_K | 3.53 GB | 3.9 GB | 4.7 GB | 7.9 GB | 12.2 GB | 36.4 GB |
| Q8_0 | 4.48 GB | 4.8 GB | 5.6 GB | 8.8 GB | 13.1 GB | 37.3 GB |
KV cache size by context length
Computed from the model's attention layout, including a fixed 0.05 GB linear-attention state.
| Context | f16 | q8_0 | q4_0 |
|---|---|---|---|
| 8k | 0.32 GB | 0.20 GB | 0.13 GB |
| 32k | 1.13 GB | 0.62 GB | 0.35 GB |
| 128k | 4.35 GB | 2.33 GB | 1.26 GB |
| 256k | 8.64 GB | 4.62 GB | 2.47 GB |
| 1M YaRN | 32.82 GB | 17.46 GB | 9.27 GB |
Which hardware runs Qwen3.5 4B? · 16k context
| Hardware | Quant | Fit | Memory | Tok/s | Speed source |
|---|---|---|---|---|---|
| RTX 5080 16GB | Q8_0 | fits fully | 5.1 GB | 183 | scaled from measured |
| Mac Studio M5 Ultra 256GB | Q8_0 | fits fully | 5.1 GB | 169 | estimated |
| Mac Studio M5 Ultra 512GB (ships late Oct 2026) | Q8_0 | fits fully | 5.1 GB | 169 | estimated |
| RTX 4090 24GB | Q8_0 | fits fully | 5.1 GB | 158 | measured |
| 2x RTX 3090 (48GB total) | Q8_0 | fits fully | 5.1 GB | 143 | estimated |
| RTX 3090 24GB | Q8_0 | fits fully | 5.1 GB | 138 | measured |
| RTX 5070 12GB | Q8_0 | fits fully | 5.1 GB | 116 | measured |
| Mac Studio M5 Max 128GB | Q8_0 | fits fully | 5.1 GB | 102 | scaled from measured |
| MacBook Pro 14/16 M5 Max 128GB | Q8_0 | fits fully | 5.1 GB | 102 | scaled from measured |
| RTX PRO 6000 96GB (bonus page) | Q8_0 | fits fully | 5.1 GB | 93 | scaled from measured |
| RTX 4070 12GB | Q8_0 | fits fully | 5.1 GB | 89 | measured |
| RTX 5090 32GB | Q8_0 | fits fully | 5.1 GB | 72 | scaled from measured |
| Mac Studio (2025) M3 Ultra 96GB | Q8_0 | fits fully | 5.1 GB | 68 | scaled from measured |
| RTX 3060 12GB (32GB RAM) | Q8_0 | fits fully | 5.1 GB | 63 | measured |
| MacBook Pro 14/16 (2024) M4 Max 128GB | Q8_0 | fits fully | 5.1 GB | 57 | scaled from measured |
| RTX 5070 Ti 16GB | Q8_0 | fits fully | 5.1 GB | 54 | scaled from measured |
| 16GB VRAM class (RTX 4060 Ti 16GB, 32GB RAM) | Q8_0 | fits fully | 5.1 GB | 54 | measured |
| NVIDIA DGX Spark 128GB | Q8_0 | fits fully | 5.1 GB | 50 | scaled from measured |
| MacBook Pro 14/16 M5 Pro 48GB | Q8_0 | fits fully | 5.1 GB | 48 | scaled from measured |
| AMD RX 7900 XTX 24GB | Q8_0 | fits fully | 5.1 GB | 46 | scaled from measured |
| 8GB VRAM class (RTX 4060 8GB, 32GB RAM) | Q8_0 | fits fully | 5.1 GB | 42 | scaled from measured |
| Mac mini (2024) M4 Pro 64GB | Q8_0 | fits fully | 5.1 GB | 35 | scaled from measured |
| Mac mini M6 32GB | Q8_0 | fits fully | 5.1 GB | 27 | scaled from measured |
| Mac mini / iMac M4 16GB | Q8_0 | fits fully | 5.1 GB | 24 | scaled from measured |
| AMD Ryzen AI Max+ 395 (Strix Halo) 128GB | Q8_0 | fits fully | 5.1 GB | 23 | scaled from measured |
| MacBook Air M5 32GB | Q8_0 | fits fully | 5.1 GB | 22 | scaled from measured |
Discrete GPUs are modelled with 32 GB of system RAM available for offload. Fits (at least with offload) on every listed configuration.
Links
Model card · GGUF files · Open in the advisor · last verified 2026-10-14
FAQ
How much VRAM does Qwen3.5 4B need?
The smallest quant (Q4_K_M) is 2.74 GB, so you need roughly 4 GB for an 8k context including KV cache and overhead. At 1M context the f16 KV cache alone is 32.8 GB.
Can I run Qwen3.5 4B on a RTX 5080 16GB?
Yes: on RTX 5080 16GB it fits fully as Q8_0 at about 183 tok/s (scaled from measured). 26 of 26 hardware configurations fit it fully at 16k context.
What is the maximum context for Qwen3.5 4B?
256k tokens natively, up to 1.01M with YaRN as documented on the model card. Memory, not the model, is usually the limit: see the KV cache table above.
All models: model index · by memory: 8 GB · 12 GB · 16 GB · 24 GB · 32 GB · 48 GB · 64 GB · 96 GB · 128 GB · 192 GB · 256 GB · 512 GB. Numbers use the same fit math as the advisor; sources and methods.