Qwen3.8 Flash Next: VRAM requirements & speed
Qwen3.8 Flash Next (180B MoE, 6B active, qwen-community-1.0). Native context 256k. Smallest GGUF: 111.33 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/Qwen3.8-Flash-Next-GGUF.
| Quant | File | +8k ctx | +32k ctx | +128k ctx | +256k ctx |
|---|---|---|---|---|---|
| Q4_K_M UD-Q4_K_XL | 111.33 GB | 111.6 GB | 112.3 GB | 114.7 GB | 117.9 GB |
| Q5_K_M UD-Q5_K_XL | 158.29 GB | 158.6 GB | 159.2 GB | 161.6 GB | 164.9 GB |
| Q8_0 | 188.23 GB | 188.5 GB | 189.2 GB | 191.6 GB | 194.8 GB |
KV cache size by context length
Computed from the model's attention layout, including a fixed 0.12 GB linear-attention state.
| Context | f16 | q8_0 | q4_0 |
|---|---|---|---|
| 8k | 0.32 GB | 0.22 GB | 0.17 GB |
| 32k | 0.92 GB | 0.55 GB | 0.34 GB |
| 128k | 3.34 GB | 1.83 GB | 1.02 GB |
| 256k | 6.56 GB | 3.54 GB | 1.93 GB |
Which hardware runs Qwen3.8 Flash Next? · 16k context
Discrete GPUs are modelled with 32 GB of system RAM available for offload. Does not fit even with offload: RTX 3090 24GB, RTX 4090 24GB, RTX 5090 32GB, RTX 3060 12GB (32GB RAM), 8GB VRAM class (RTX 4060 8GB, 32GB RAM), 16GB VRAM class (RTX 4060 Ti 16GB, 32GB RAM), RTX 5070 12GB, RTX 4070 12GB, RTX 5070 Ti 16GB, RTX 5080 16GB, AMD RX 7900 XTX 24GB, AMD Ryzen AI Max+ 395 (Strix Halo) 128GB, NVIDIA DGX Spark 128GB, Mac Studio (2025) M3 Ultra 96GB, MacBook Pro 14/16 (2024) M4 Max 128GB, Mac mini / iMac M4 16GB, Mac mini (2024) M4 Pro 64GB, 2x RTX 3090 (48GB total), Mac Studio M5 Max 128GB, MacBook Pro 14/16 M5 Max 128GB, MacBook Pro 14/16 M5 Pro 48GB, Mac mini M6 32GB, MacBook Air M5 32GB, RTX 5060 Ti 16GB.
MLX conversions for Apple Silicon
| Repo | Bits | Size | Runs with |
|---|---|---|---|
| mlx-community/Qwen3.8-Flash-Next-4bit | 4-bit (4bit) | 111.5 GB | mlx-vlm |
Verified via the Hugging Face API on 2026-10-20. Compare with the GGUF sizes above (Q4_K_M 111.33 GB, Q8_0 188.23 GB). Mac hardware pages show the MLX command; there are no MLX speeds on this site yet. MLX vs GGUF.
Links
Model card · GGUF files · Open in the advisor · last verified 2026-10-20
FAQ
How much VRAM does Qwen3.8 Flash Next need?
The smallest quant (Q4_K_M) is 111.33 GB, so you need roughly 113 GB for an 8k context including KV cache and overhead. At 256k context the f16 KV cache alone is 6.6 GB.
Can I run Qwen3.8 Flash Next on a Mac Studio M5 Ultra 256GB?
Yes: on Mac Studio M5 Ultra 256GB it fits fully as UD-Q5_K_XL at about 111 tok/s (estimated). 3 of 28 hardware configurations fit it fully at 16k context.
What is the maximum context for Qwen3.8 Flash Next?
256k tokens natively. 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.