Can the RTX 3090 24 GB run FLUX.2 [dev]?
Not at full quality. The 16-bit and 8-bit files are too big for the RTX 3090 24 GB; the largest that fits is Q4_K_M (20.1 GB).
Q4_K_M (20.1 GB) fits with only 0.6 GB to spare (about 23.4 GB of 24 GB). Quality: good; some loss in fine detail and text.
Also try the FP8 file (35.5 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 | flux2-dev-Q4_K_M.gguf Q4_K_M · city96/FLUX.2-dev-gguf | models/unet | 20.1 GB | Download → |
| Text encoder | mistral_3_small_flux2_fp8.safetensors Mistral 3 Small FP8 · Comfy-Org/flux2-dev | models/text_encoders | 18.0 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 | 38.5 GB | |||
Alternatives: Mistral 3 Small BF16 (35.6 GB). Sizes from Hugging Face, 2026-10-01.
System RAM: 48 GB or more. These files take about 38.5 GB of RAM while loaded, 44.5 GB with Windows and ComfyUI. What happens with less. calculated
02Every FLUX.2 dev file on 24 GB
| File | Size | Needed | On this card | Quality | Download |
|---|---|---|---|---|---|
| 16-bit SAFETENSORS · black-forest-labs | 64.4 GB | 67.7 GB | 43.7 GB too big | the original weights | Hugging Face → |
| Q8_0 GGUF · city96 | 35.0 GB | 38.3 GB | 14.3 GB too big | practically identical to the original | Hugging Face → |
| FP8 SAFETENSORS · Comfy-Org | 35.5 GB | 38.8 GB | 14.8 GB too big | practically identical to the original | Hugging Face → |
| Q6_K GGUF · city96 | 27.4 GB | 30.7 GB | 6.7 GB too big | very close to the original | Hugging Face → |
| Q5_K_M GGUF · city96 | 24.1 GB | 27.4 GB | 3.4 GB too big | close; small differences in fine detail | Hugging Face → |
| Q4_K_M ← GGUF · city96 | 20.1 GB | 23.4 GB | fits · 0.6 GB spare | good; some loss in fine detail and text | Hugging Face → |
| Q3_K_M GGUF · city96 | 16.0 GB | 19.3 GB | fits · 4.7 GB spare | noticeable loss of detail | Hugging Face → |
| Q2_K GGUF · city96 | 12.9 GB | 16.2 GB | fits · 7.8 GB spare | heavy loss; a last resort | Hugging Face → |
“Needed” adds 2.5 GB of working memory for FLUX.2 dev 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 dev on a RTX 3090 24 GB, send your time per image and peak VRAM and it will appear here, credited.
04With more VRAM
With 48 GB you could run FLUX.2 dev at 8-bit or better (Q8_0, 35.0 GB) with no offloading.
What changes from the RTX 3090 24 GB to the RTX 4090 24 GB → · What changes from the RTX 3090 24 GB to the RTX 5090 32 GB →
05About the RTX 3090 24 GB
The RTX 3090 24 GB (Ampere) has no FP8 compute. FP8 files still load and save memory, but ComfyUI converts them back before the maths, so there is no speed gain - Q8_0 GGUF is the closer-to-original 8-bit choice. ComfyUI can compute INT8 files natively on NVIDIA, which is worth a try where a model offers one.
24 GB GDDR6X · 384-bit · 936 GB/s · Ampere. Everything that runs on it →
06Questions
How much VRAM does FLUX.2 dev need?
Around 16.2 GB with the smallest file (Q2_K) and 38.8 GB with an 8-bit file (FP8). The full 16-bit file needs about 67.7 GB.
Which FLUX.2 dev file should I download for the RTX 3090 24 GB?
Q4_K_M (20.1 GB) from city96/FLUX.2-dev-gguf. Load it with Unet Loader (GGUF) from the ComfyUI-GGUF node pack.
FP8 or Q8_0 for FLUX.2 dev on the RTX 3090 24 GB?
Q8_0 (35.0 GB). The RTX 3090 24 GB has no FP8 maths, so FP8 (35.5 GB) only saves memory and is a step further from the original.
How much do I need to download for FLUX.2 dev on the RTX 3090 24 GB?
38.5 GB: flux2-dev-Q4_K_M.gguf, mistral_3_small_flux2_fp8.safetensors, flux2-vae.safetensors.