Can the RTX 5090 32 GB run FLUX.2 [klein] 9B?
Yes. 16-bit fits on the RTX 5090 32 GB with 11.5 GB to spare.
16-bit (18.2 GB) needs about 20.5 GB in use, so 11.5 GB of the 32 GB stays free: room for a larger image, a LoRA or a ControlNet.
01What to download
| Part | File | Folder | Size | |
|---|---|---|---|---|
| Model | flux-2-klein-9b.safetensors 16-bit · black-forest-labs/FLUX.2-klein-9B | models/diffusion_models | 18.2 GB | Download → |
| Text encoder | qwen_3_8b_fp8mixed.safetensors Qwen3 8B FP8 · Comfy-Org/flux2-klein-9B | models/text_encoders | 8.7 GB | Download → |
| VAE | flux2-vae.safetensors FLUX.2 VAE · Comfy-Org/flux2-dev | models/vae | 0.3 GB | Download → |
| Total download · keep about the same free on disk | 27.2 GB | |||
Alternatives: Qwen3 8B BF16 (16.4 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 →
System RAM: 48 GB or more. These files take about 27.2 GB of RAM while loaded, 33.2 GB with Windows and ComfyUI. What happens with less. calculated
02Every FLUX.2 klein 9B file on 32 GB
| File | Size | Needed | On this card | Quality | Download |
|---|---|---|---|---|---|
| 16-bit ← SAFETENSORS · black-forest-labs | 18.2 GB | 20.5 GB | fits · 11.5 GB spare | the original weights | Hugging Face → |
| FP8 SAFETENSORS · black-forest-labs | 9.4 GB | 11.7 GB | fits · 20.3 GB spare | practically identical to the original | Hugging Face → |
| Q8_0 GGUF · unsloth | 10.0 GB | 12.3 GB | fits · 19.7 GB spare | practically identical to the original | Hugging Face → |
| Q6_K GGUF · unsloth | 7.9 GB | 10.2 GB | fits · 21.8 GB spare | very close to the original | Hugging Face → |
| Q5_K_M GGUF · unsloth | 7.0 GB | 9.3 GB | fits · 22.7 GB spare | close; small differences in fine detail | Hugging Face → |
| Q4_K_M GGUF · unsloth | 5.9 GB | 8.2 GB | fits · 23.8 GB spare | good; some loss in fine detail and text | Hugging Face → |
| Q3_K_M GGUF · unsloth | 4.8 GB | 7.1 GB | fits · 24.9 GB spare | noticeable loss of detail | Hugging Face → |
| Q2_K GGUF · unsloth | 4.0 GB | 6.3 GB | fits · 25.7 GB spare | heavy loss; a last resort | Hugging Face → |
“Needed” adds 1.5 GB of working memory for FLUX.2 klein 9B 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.2 klein 9B 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.2 klein 9B need?
Around 6.3 GB with the smallest file (Q2_K) and 11.7 GB with an 8-bit file (FP8). The full 16-bit file needs about 20.5 GB.
Which FLUX.2 klein 9B file should I download for the RTX 5090 32 GB?
16-bit (18.2 GB) from black-forest-labs/FLUX.2-klein-9B.
FP8 or Q8_0 for FLUX.2 klein 9B on the RTX 5090 32 GB?
FP8 (9.4 GB): the RTX 5090 32 GB computes it natively, while Q8_0 (10.0 GB) is unpacked on the fly.
How much do I need to download for FLUX.2 klein 9B on the RTX 5090 32 GB?
27.2 GB: flux-2-klein-9b.safetensors, qwen_3_8b_fp8mixed.safetensors, flux2-vae.safetensors.