FLUX.2 [dev] on 16 GB of VRAM
Not entirely. Even Q2_K is 0.2 GB over 16 GB, so ComfyUI keeps part of it in system RAM. The 32B second-generation FLUX. Very capable and very heavy: even 4-bit files are around 20 GB, and the text encoder is a 24B language model.
Nothing fits entirely, but Q2_K (12.9 GB) overflows by only about 0.2 GB. ComfyUI keeps that part in system RAM automatically: slower than a full fit, but usable.
Also try the FP8 file (35.5 GB) on NVIDIA GPUs. 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 →
01Other amounts of VRAM
02Every file, on 16 GB
| File | Size | Needed | On this card | Quality | Download |
|---|---|---|---|---|---|
| 16-bit SAFETENSORS · black-forest-labs | 64.4 GB | 67.7 GB | 51.7 GB too big | the original weights | Hugging Face → |
| Q8_0 GGUF · city96 | 35.0 GB | 38.3 GB | 22.3 GB too big | practically identical to the original | Hugging Face → |
| FP8 SAFETENSORS · Comfy-Org | 35.5 GB | 38.8 GB | 22.8 GB too big | practically identical to the original | Hugging Face → |
| Q6_K GGUF · city96 | 27.4 GB | 30.7 GB | 14.7 GB too big | very close to the original | Hugging Face → |
| Q5_K_M GGUF · city96 | 24.1 GB | 27.4 GB | 11.4 GB too big | close; small differences in fine detail | Hugging Face → |
| Q4_K_M GGUF · city96 | 20.1 GB | 23.4 GB | 7.4 GB too big | good; some loss in fine detail and text | Hugging Face → |
| Q3_K_M GGUF · city96 | 16.0 GB | 19.3 GB | 3.3 GB too big | noticeable loss of detail | Hugging Face → |
| Q2_K ← GGUF · city96 | 12.9 GB | 16.2 GB | spills 0.2 GB | 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.
03What to download
| Part | File | Folder | Size | |
|---|---|---|---|---|
| Model | flux2-dev-Q2_K.gguf Q2_K · city96/FLUX.2-dev-gguf | models/unet | 12.9 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 | 31.2 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 31.2 GB of RAM while loaded, 37.2 GB with Windows and ComfyUI. What happens with less. calculated
04The text encoder
At 18.0 GB even the smallest Mistral Small 3 (24B) file is too big for 16 GB, so it runs from system RAM. That slows down reading the prompt, not the picture. Sizes: 16-bit 35.6 GB, FP8 18.0 GB. Why the encoder does not count against VRAM →