Can the RTX 5090 32 GB run FLUX.1 Fill [dev]?
Yes. 16-bit fits on the RTX 5090 32 GB with 5.6 GB to spare.
Take 16-bit (23.8 GB). In use it comes to about 26.4 GB, with 5.6 GB left over on 32 GB.
01What to download
| Part | File | Folder | Size | |
|---|---|---|---|---|
| Model | flux1-fill-dev.safetensors 16-bit · black-forest-labs/FLUX.1-Fill-dev | models/diffusion_models | 23.8 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 | 29.3 GB | |||
Alternatives: T5-XXL FP16 (9.8 GB). Sizes from Hugging Face, 2026-10-01.
System RAM: 48 GB or more. These files take about 29.3 GB of RAM while loaded, 35.3 GB with Windows and ComfyUI. What happens with less. calculated
02Every FLUX.1 Fill file on 32 GB
| File | Size | Needed | On this card | Quality | Download |
|---|---|---|---|---|---|
| 16-bit ← SAFETENSORS · black-forest-labs | 23.8 GB | 26.4 GB | fits · 5.6 GB spare | the original weights | Hugging Face → |
| Q8_0 GGUF · YarvixPA | 12.7 GB | 15.3 GB | fits · 16.7 GB spare | practically identical to the original | Hugging Face → |
| Q6_K GGUF · YarvixPA | 9.9 GB | 12.5 GB | fits · 19.5 GB spare | very close to the original | Hugging Face → |
| Q5_K_S GGUF · YarvixPA | 8.3 GB | 10.9 GB | fits · 21.1 GB spare | close; small differences in fine detail | Hugging Face → |
| Q4_K_S GGUF · YarvixPA | 6.8 GB | 9.4 GB | fits · 22.6 GB spare | good; some loss in fine detail and text | Hugging Face → |
| Q3_K_S GGUF · YarvixPA | 5.2 GB | 7.8 GB | fits · 24.2 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 5090 32 GB, send your time per image and peak VRAM and it will appear here, credited.
04About the RTX 5090 32 GB
The RTX 5090 32 GB is a Blackwell GPU with FP8 and FP4 hardware: ComfyUI computes Comfy-Org's FP8 files natively here, and NVFP4 files (where a model offers them) are faster still.
32 GB GDDR7 · 512-bit · 1792 GB/s · Blackwell. Everything that runs on it →
05Questions
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 5090 32 GB?
16-bit (23.8 GB) from black-forest-labs/FLUX.1-Fill-dev.
How much do I need to download for FLUX.1 Fill on the RTX 5090 32 GB?
29.3 GB: flux1-fill-dev.safetensors, t5xxl_fp8_e4m3fn.safetensors, clip_l.safetensors, ae.safetensors.