Can the RX 9070 XT 16 GB run Stable Diffusion 1.5?
Download 16-bit (2.1 GB). With the model's working memory it needs about 3.3 GB, leaving 12.7 GB spare on 16 GB. Quality: the original weights.
01What to download
| Part | File | Folder | Size | |
|---|---|---|---|---|
| Checkpoint | v1-5-pruned-emaonly-fp16.safetensors 16-bit · Comfy-Org/stable-diffusion-v1-5-archive | models/checkpoints | 2.1 GB | Download → |
| Total download · keep about the same free on disk | 2.1 GB | |||
One file: the checkpoint already contains the text encoders and the VAE. 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: 16 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 2.1 GB, plus roughly 6 GB for Windows, ComfyUI and a browser: 8.1 GB in total. With less RAM it still runs, but Windows starts swapping to disk and loading gets very slow. calculated
02Every SD 1.5 file on 16 GB
| File | Size | Needed | On this card | Quality | Download |
|---|---|---|---|---|---|
| 16-bit ← SAFETENSORS · Comfy-Org | 2.1 GB | 3.3 GB | fits · 12.7 GB spare | the original weights | Hugging Face → |
Sizes from the Hugging Face file listing, read 2026-09-25. “Needed” = file + 0.8 GB working memory for this model + 0.8 GB kept free for the system. The 2.13 GB checkpoint also holds the text encoder and VAE; the UNet alone is about 1.7 GB at 16-bit.
03The text encoder
The text encoder is inside the checkpoint, so there is nothing extra to download.
04About this GPU
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. RX 9000 (RDNA 4) GPUs have FP8 hardware, and ComfyUI computes FP8 natively on them with PyTorch 2.7+ and ROCm 6.4+.
RX 9070 XT 16 GB: 16 GB GDDR6 · 256-bit · 640 GB/s · RDNA 4. Everything that runs on the RX 9070 XT 16 GB →
05What more VRAM would change
Nothing to gain for this model: the RX 9070 XT 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 1.5 on a RX 9070 XT 16 GB, send your time per image and peak VRAM and it will appear here, credited.
07Questions
How much VRAM does SD 1.5 need?
Around 3.3 GB with the smallest file (16-bit), counting working memory and a small system reserve.
Which SD 1.5 file should I download for the RX 9070 XT 16 GB?
16-bit (2.1 GB) from Comfy-Org/stable-diffusion-v1-5-archive.
Is FP8 faster than GGUF on the RX 9070 XT 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 1.5 on the RX 9070 XT 16 GB?
About 2.1 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, 16 GB of system RAM or more is recommended.