Can the RX 7900 XTX 24 GB run Stable Diffusion 3.5 Large?
Yes. 16-bit fits on the RX 7900 XTX 24 GB with 5.2 GB to spare.
Take 16-bit (16.5 GB). In use it comes to about 18.8 GB, with 5.2 GB left over on 24 GB.
01What to download
| Part | File | Folder | Size | |
|---|---|---|---|---|
| Model | sd3.5_large.safetensors 16-bit · stabilityai/stable-diffusion-3.5-large | models/diffusion_models | 16.5 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 | 23.2 GB | |||
Alternatives: T5-XXL FP16 (9.8 GB). Sizes from Hugging Face, 2026-10-01.
02Every SD 3.5 Large file on 24 GB
| File | Size | Needed | On this card | Quality | Download |
|---|---|---|---|---|---|
| 16-bit ← SAFETENSORS · stabilityai | 16.5 GB | 18.8 GB | fits · 5.2 GB spare | the original weights | Hugging Face → |
| Q8_0 GGUF · city96 | 8.8 GB | 11.1 GB | fits · 12.9 GB spare | practically identical to the original | Hugging Face → |
| Q5_1 GGUF · city96 | 6.3 GB | 8.6 GB | fits · 15.4 GB spare | close; small differences in fine detail | Hugging Face → |
| Q4_1 GGUF · city96 | 5.3 GB | 7.6 GB | fits · 16.4 GB spare | 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.
03Measured and reported results
Nobody has sent measured numbers for this pair yet. If you run SD 3.5 Large on a RX 7900 XTX 24 GB, send your time per image and peak VRAM and it will appear here, credited.
04About the RX 7900 XTX 24 GB
ComfyUI supports AMD GPUs on Windows officially since v0.7.0 (January 2026), through ROCm. Memory works the same as on NVIDIA, so the fit verdicts apply. Some custom nodes are NVIDIA-only. RDNA 3 has no FP8 compute, so FP8 files save memory but give no speed-up.
24 GB GDDR6 · 384-bit · 960 GB/s · RDNA 3. Everything that runs on it →
05Questions
How much VRAM does SD 3.5 Large need?
Around 7.6 GB with the smallest file (Q4_1) and 11.1 GB with an 8-bit file (Q8_0). The full 16-bit file needs about 18.8 GB.
Which SD 3.5 Large file should I download for the RX 7900 XTX 24 GB?
16-bit (16.5 GB) from stabilityai/stable-diffusion-3.5-large.
How much do I need to download for SD 3.5 Large on the RX 7900 XTX 24 GB?
23.2 GB: sd3.5_large.safetensors, t5xxl_fp8_e4m3fn.safetensors, clip_l.safetensors, clip_g.safetensors, diffusion_pytorch_model.safetensors.