Can the RTX 4070 Laptop 8 GB run FLUX.1 Fill [dev]?
Not at full quality. The 16-bit and 8-bit files are too big for the RTX 4070 Laptop 8 GB; the largest that fits is Q3_K_S (5.2 GB).
Q3_K_S (5.2 GB) fits with only 0.2 GB to spare (about 7.8 GB of 8 GB). Quality: noticeable loss of detail. For better quality, Q4_K_S (6.8 GB) also runs, with about 1.4 GB spilling into system RAM - a little slower, still practical.
01What to download
| Part | File | Folder | Size | |
|---|---|---|---|---|
| Model | flux1-fill-dev-Q3_K_S.gguf Q3_K_S · YarvixPA/FLUX.1-Fill-dev-GGUF | models/unet | 5.2 GB | Download → |
| Text encoder | t5xxl_fp8_e4m3fn.safetensors T5-XXL FP8 · comfyanonymous/flux_text_encoders | models/text_encoders | 4.9 GB | Download → |
| Text encoder | clip_l.safetensors CLIP-L · comfyanonymous/flux_text_encoders | models/text_encoders | 0.2 GB | Download → |
| VAE | ae.safetensors FLUX.1 VAE (ae) · Comfy-Org/Lumina_Image_2.0_Repackaged | models/vae | 0.3 GB | Download → |
| Total download · keep about the same free on disk | 10.7 GB | |||
Alternatives: T5-XXL FP16 (9.8 GB). Sizes from Hugging Face, 2026-10-01.
02Every FLUX.1 Fill file on 8 GB
| File | Size | Needed | On this card | Quality | Download |
|---|---|---|---|---|---|
| 16-bit SAFETENSORS · black-forest-labs | 23.8 GB | 26.4 GB | 18.4 GB too big | the original weights | Hugging Face → |
| Q8_0 GGUF · YarvixPA | 12.7 GB | 15.3 GB | 7.3 GB too big | practically identical to the original | Hugging Face → |
| Q6_K GGUF · YarvixPA | 9.9 GB | 12.5 GB | 4.5 GB too big | very close to the original | Hugging Face → |
| Q5_K_S GGUF · YarvixPA | 8.3 GB | 10.9 GB | 2.9 GB too big | close; small differences in fine detail | Hugging Face → |
| Q4_K_S GGUF · YarvixPA | 6.8 GB | 9.4 GB | spills 1.4 GB | good; some loss in fine detail and text | Hugging Face → |
| Q3_K_S ← GGUF · YarvixPA | 5.2 GB | 7.8 GB | fits · 0.2 GB spare | noticeable loss of detail | Hugging Face → |
“Needed” adds 1.8 GB of working memory for FLUX.1 Fill and a 0.8 GB reserve. Sizes 2026-10-01.
03Measured and reported results
Nobody has sent measured numbers for this pair yet. If you run FLUX.1 Fill on a RTX 4070 Laptop 8 GB, send your time per image and peak VRAM and it will appear here, credited.
04With more VRAM
With 16 GB you could run FLUX.1 Fill at 8-bit or better (Q8_0, 12.7 GB) with no offloading: for example on the RTX 5080 16 GB, RTX 5070 Ti 16 GB, RTX 5060 Ti 16 GB.
What changes from the RTX 4070 Laptop 8 GB to the RTX 3090 24 GB →
05About the RTX 4070 Laptop 8 GB
The RTX 4070 Laptop 8 GB is an Ada Lovelace GPU with hardware FP8, so ComfyUI can compute Comfy-Org's FP8 files natively: small and fast. (Plain FP8 files use FP8 maths with the --fast fp8_matrix_mult option.) As a laptop GPU it runs at a lower power limit than desktop cards (35–115 W depending on the laptop). The memory verdicts are the same; speed depends heavily on how much power the laptop maker allows.
8 GB GDDR6 · 128-bit · Ada Lovelace · 35–115 W. Everything that runs on it →
06Questions
How much VRAM does FLUX.1 Fill need?
Around 7.8 GB with the smallest file (Q3_K_S) and 15.3 GB with an 8-bit file (Q8_0). The full 16-bit file needs about 26.4 GB.
Which FLUX.1 Fill file should I download for the RTX 4070 Laptop 8 GB?
Q3_K_S (5.2 GB) from YarvixPA/FLUX.1-Fill-dev-GGUF. Load it with Unet Loader (GGUF) from the ComfyUI-GGUF node pack.
How much do I need to download for FLUX.1 Fill on the RTX 4070 Laptop 8 GB?
10.7 GB: flux1-fill-dev-Q3_K_S.gguf, t5xxl_fp8_e4m3fn.safetensors, clip_l.safetensors, ae.safetensors.