Can the RTX 4070 Laptop 8 GB run FLUX.1 [schnell]?
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 0.5 GB to spare (about 7.5 GB of 8 GB). Quality: noticeable loss of detail. For better quality, Q4_K_S (6.8 GB) also runs, with about 1.1 GB spilling into system RAM - a little slower, still practical.
Also try the FP8 file (11.9 GB) on this GPU. It does not fit entirely, but a current ComfyUI streams the overflow from RAM and native 8-bit files often beat a small GGUF that does fit. Dynamic VRAM →
01What to download
| Part | File | Folder | Size | |
|---|---|---|---|---|
| Model | flux1-schnell-Q3_K_S.gguf Q3_K_S · city96/FLUX.1-schnell-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.
Free ComfyUI workflow, tested on my RTX 5060 Ti: GGUF Q8_0 workflow (.json). Drag the file into ComfyUI. All workflows →
02Every FLUX.1 schnell file on 8 GB
| File | Size | Needed | On this card | Quality | Download |
|---|---|---|---|---|---|
| 16-bit SAFETENSORS · black-forest-labs | 23.8 GB | 26.1 GB | 18.1 GB too big | the original weights | Hugging Face → |
| FP8 SAFETENSORS · Kijai | 11.9 GB | 14.2 GB | 6.2 GB too big | practically identical to the original | Hugging Face → |
| Q8_0 GGUF · city96 | 12.7 GB | 15.0 GB | 7.0 GB too big | practically identical to the original | Hugging Face → |
| Q6_K GGUF · city96 | 9.8 GB | 12.1 GB | 4.1 GB too big | very close to the original | Hugging Face → |
| Q5_K_S GGUF · city96 | 8.3 GB | 10.6 GB | 2.6 GB too big | close; small differences in fine detail | Hugging Face → |
| Q4_K_S GGUF · city96 | 6.8 GB | 9.1 GB | spills 1.1 GB | good; some loss in fine detail and text | Hugging Face → |
| Q3_K_S ← GGUF · city96 | 5.2 GB | 7.5 GB | fits · 0.5 GB spare | noticeable loss of detail | Hugging Face → |
| Q2_K GGUF · city96 | 4.0 GB | 6.3 GB | fits · 1.7 GB spare | heavy loss; a last resort | Hugging Face → |
“Needed” adds 1.5 GB of working memory for FLUX.1 schnell 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 schnell 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 schnell at 8-bit or better (FP8, 11.9 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 schnell need?
Around 6.3 GB with the smallest file (Q2_K) and 14.2 GB with an 8-bit file (FP8). The full 16-bit file needs about 26.1 GB.
Which FLUX.1 schnell file should I download for the RTX 4070 Laptop 8 GB?
Q3_K_S (5.2 GB) from city96/FLUX.1-schnell-gguf. Load it with Unet Loader (GGUF) from the ComfyUI-GGUF node pack.
FP8 or Q8_0 for FLUX.1 schnell on the RTX 4070 Laptop 8 GB?
FP8 (11.9 GB): the RTX 4070 Laptop 8 GB computes it natively, while Q8_0 (12.7 GB) is unpacked on the fly.
How much do I need to download for FLUX.1 schnell on the RTX 4070 Laptop 8 GB?
10.7 GB: flux1-schnell-Q3_K_S.gguf, t5xxl_fp8_e4m3fn.safetensors, clip_l.safetensors, ae.safetensors.