Stable Diffusion 3.5 Large on 6 GB of VRAM
Not entirely. Even Q4_1 is 1.6 GB over 6 GB, so ComfyUI keeps part of it in system RAM. Stability AI's 8B model. City96 only publishes the older GGUF types for it (Q8_0, Q5, Q4), not K-quants.
Offload
Not entirely in VRAM, but it can still run.
Nothing fits entirely, but Q4_1 (5.3 GB) overflows by only about 1.6 GB. ComfyUI keeps that part in system RAM automatically: slower than a full fit, but usable.
Best fileQ4_1
File size5.3 GB
VRAM needed~7.6 GB
System RAM32 GB+
Memory map · 6 GB GPU7.6 GB needed · 1.6 GB over 6 GB
04 GB8 GB
Weights Q4_1 · 5.3 GBWorking memory · 1.5 GBReserve · 0.8 GBSpills to system RAM · 1.6 GB
calculated How this is counted.
01Other amounts of VRAM
02Every file, on 6 GB
| File | Size | Needed | On this card | Quality | Download |
|---|---|---|---|---|---|
| 16-bit SAFETENSORS · stabilityai | 16.5 GB | 18.8 GB | 12.8 GB too big | the original weights | Hugging Face → |
| Q8_0 GGUF · city96 | 8.8 GB | 11.1 GB | 5.1 GB too big | practically identical to the original | Hugging Face → |
| Q5_1 GGUF · city96 | 6.3 GB | 8.6 GB | 2.6 GB too big | close; small differences in fine detail | Hugging Face → |
| Q4_1 ← GGUF · city96 | 5.3 GB | 7.6 GB | spills 1.6 GB | good; some loss in fine detail and text | Hugging Face → |
“Needed” adds 1.5 GB of working memory for SD 3.5 Large and a 0.8 GB reserve. Sizes 2026-10-01.
03What to download
| Part | File | Folder | Size | |
|---|---|---|---|---|
| Model | sd3.5_large-Q4_1.gguf Q4_1 · city96/stable-diffusion-3.5-large-gguf | models/unet | 5.3 GB | Download → |
| Text encoder | t5xxl_fp8_e4m3fn.safetensors T5-XXL FP8 · Comfy-Org/stable-diffusion-3.5-fp8 | models/text_encoders | 4.9 GB | Download → |
| Text encoder | clip_l.safetensors CLIP-L · Comfy-Org/stable-diffusion-3.5-fp8 | models/text_encoders | 0.2 GB | Download → |
| Text encoder | clip_g.safetensors CLIP-G · Comfy-Org/stable-diffusion-3.5-fp8 | models/text_encoders | 1.4 GB | Download → |
| VAE | diffusion_pytorch_model.safetensors SD 3.5 VAE (gated repo: log in and accept the licence first) · stabilityai/stable-diffusion-3.5-large | models/vae | 0.2 GB | Download → |
| Total download · keep about the same free on disk | 12.0 GB | |||
Alternatives: T5-XXL FP16 (9.8 GB). Sizes from Hugging Face, 2026-10-01.