Can the RTX 4070 Ti Super 16 GB run Stable Diffusion 3.5 Large?
Download Q8_0 (8.8 GB). With the model's working memory it needs about 11.1 GB, leaving 4.9 GB spare on 16 GB. Quality: practically identical to the original.
01What to download
| Part | File | Folder | Size | |
|---|---|---|---|---|
| Model | sd3.5_large-Q8_0.gguf Q8_0 · city96/stable-diffusion-3.5-large-gguf | models/unet | 8.8 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 → |
| Total download · keep about the same free on disk | 15.3 GB | |||
Alternatives: T5-XXL FP16 (9.8 GB). The 16-bit text encoder is a little more faithful; the smaller one is chosen here because it loads faster and needs less RAM. Sizes read from Hugging Face (2026-09-25). “Download” links start the file directly; the file name links are the same files the official ComfyUI workflows use.
System RAM: 32 GB or more. ComfyUI keeps the model file, the text encoder and the VAE in system RAM and moves them to the GPU as needed. With this set of files that is about 15.3 GB, plus roughly 6 GB for Windows, ComfyUI and a browser: 21.3 GB in total. With less RAM it still runs, but Windows starts swapping to disk and loading gets very slow. calculated
02Every SD 3.5 Large file on 16 GB
| File | Size | Needed | On this card | Quality | Download |
|---|---|---|---|---|---|
| 16-bit SAFETENSORS · stabilityai | 16.5 GB | 18.8 GB | 2.8 GB too big | the original weights | Hugging Face → |
| Q8_0 ← GGUF · city96 | 8.8 GB | 11.1 GB | fits · 4.9 GB spare | practically identical to the original | Hugging Face → |
| Q5_1 GGUF · city96 | 6.3 GB | 8.6 GB | fits · 7.4 GB spare | close; small differences in fine detail | Hugging Face → |
| Q4_1 GGUF · city96 | 5.3 GB | 7.6 GB | fits · 8.4 GB spare | good; some loss in fine detail and text | Hugging Face → |
Sizes from the Hugging Face file listing, read 2026-09-25. “Needed” = file + 1.5 GB working memory for this model + 0.8 GB kept free for the system.
03The text encoder
CLIP-L + CLIP-G + T5-XXL: 9.8 GB as 16-bit, 4.9 GB as FP8 (T5-XXL sizes shown; CLIP-L and CLIP-G add about 1.6 GB). ComfyUI encodes the prompt first and can push the encoder out of VRAM before sampling, so it does not have to fit together with the model. On 16 GB the FP8 encoder fits on its own, so prompt encoding stays fast.
04About this GPU
The RTX 4070 Ti Super 16 GB is an Ada Lovelace GPU with hardware FP8, so ComfyUI can compute Comfy-Org's FP8 files natively: small and fast. (Plain FP8 files use FP8 maths with the --fast fp8_matrix_mult option.)
RTX 4070 Ti Super 16 GB: 16 GB GDDR6X · 256-bit · 672 GB/s · Ada Lovelace. Everything that runs on the RTX 4070 Ti Super 16 GB →
05What more VRAM would change
Nothing to gain for this model: the RTX 4070 Ti Super 16 GB already runs a top-quality file entirely in VRAM. More memory would only help with bigger images, longer clips or several models at once.
06Measured and reported results
Nobody has sent measured numbers for this pair yet. If you run SD 3.5 Large on a RTX 4070 Ti Super 16 GB, send your time per image and peak VRAM and it will appear here, credited.
07Questions
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), counting working memory and a small system reserve. The full 16-bit file needs about 18.8 GB.
Which SD 3.5 Large file should I download for the RTX 4070 Ti Super 16 GB?
Q8_0 (8.8 GB) from city96/stable-diffusion-3.5-large-gguf. Load it with Unet Loader (GGUF) from the ComfyUI-GGUF node pack.
Is FP8 faster than GGUF on the RTX 4070 Ti Super 16 GB?
It can be. This GPU has FP8 hardware, and ComfyUI computes FP8 natively for files made for it (Comfy-Org's fp8_scaled files), or for any FP8 file with the --fast fp8_matrix_mult option. GGUF files are unpacked on the fly, which costs some speed.
How much do I need to download for SD 3.5 Large on the RTX 4070 Ti Super 16 GB?
About 15.3 GB for the model file, text encoder and VAE listed on this page, and the same again free on disk. With a 16 GB card, 32 GB of system RAM or more is recommended.