An RTX 4070 holds 12 GB of VRAM and pushes tens of teraflops, enough to run a distilled SDXL model in a handful of steps. That card sits idle while you wait in a cloud queue and pay per image to render on someone else's GPU. Off Grid AI Desktop is a free, open-source app that runs RealVisXL Lightning directly on your PC or Mac.
Free, open-source, runs fully offline.
On-device image generation in Off Grid AI Desktop. SDXL, Lightning, Turbo, and more, run from your chat.
Why RealVisXL Lightning
RealVisXL v5.0 is a photorealistic SDXL checkpoint. The Lightning variant is distilled for few-step generation, so it produces a finished image in roughly 4 to 8 steps instead of the 25 to 40 a standard SDXL model needs. Fewer steps means each render finishes in a fraction of the time, which changes how you work: you iterate on prompts in near real time instead of waiting between every attempt.
You keep the photorealism RealVisXL is known for, and you get it fast. We publish it in GGUF for stable-diffusion.cpp:
RealVisXL v5.0 Lightning on Hugging Face →
The GGUF build quantizes the weights so they fit on a consumer card. Download one file, point the app at it, generate. No Python, no diffusers, no toolkit install.
What You Need
Two tiers. Find your row.
| Tier | Windows | macOS |
|---|---|---|
| Minimum | NVIDIA GPU with 8 GB VRAM (or Vulkan-capable), 16 GB RAM, 12 GB free disk | M1, 16 GB unified memory, macOS 13+, 12 GB free disk |
| Recommended | RTX 4070 12 GB or better, 32 GB RAM | M3 / M4 Pro or Max, 24 GB+ unified memory |
Because Lightning runs so few steps, it is forgiving on slower hardware. A CPU-only Windows box can still produce an image, just at a slower pace per step.
What Off Grid AI Desktop Can Do
The image studio sits inside a full local AI app. For fast photorealistic work, here is what you get.
- Generate a photorealistic image in 4 to 8 steps, fully on-device.
- See each step render live, with progress and an ETA, plus a cancel button.
- Refine an existing photo with img2img.
- Apply style presets (Cinematic, Sketch, Anime, and more) on top of the base model.
- Keep every render in an artifacts gallery with a lightbox.
The same window gives you local LLM chat, voice in and out, and a Hugging Face model browser, so you can draft a prompt with a local model and render it without switching apps.
How Hardware Acceleration Works
On Windows, Off Grid AI Desktop runs stable-diffusion.cpp on CUDA for NVIDIA cards or Vulkan for broader GPU support, with a CPU fallback when no GPU is available. Lightning's low step count means even the CPU path stays usable for occasional renders.
On a Mac, the engine uses Metal. Apple Silicon shares one memory pool between CPU and GPU, so weights are not copied across a bus, and a 16 GB MacBook can run a checkpoint a discrete 8 GB card would handle on a PC.
Quantization makes the file fit. The GGUF build trades a little precision for a much smaller download, and at SDXL resolution the difference is hard to see. Pair that with few-step distillation and you have the fastest practical way to run photorealistic SDXL on your own hardware.
Keeping It Fast
Lightning is already fast. These tips keep it that way.
- Stay in the model's intended step range. Lightning checkpoints want low step counts. Cranking steps up does not improve quality and only costs time.
- Use a low CFG scale. Distilled models are tuned for it, and high CFG can wash out the realism.
- Generate at 1024x1024 native, then upscale a keeper rather than rendering everything large.
- On Windows, confirm the CUDA path is active so you are not silently falling back to CPU.
Privacy: Stronger Than DALL-E
DALL-E runs on OpenAI's servers. Your prompts pass through their API, get logged, and are subject to their content filters. Off Grid AI Desktop inverts that.
Your prompt never leaves the machine. The image is computed locally and written to your disk. No account, no telemetry, no API key. The app is AGPL-3.0, so you can audit the source. Disconnect from the internet and it keeps generating.
Getting Started
- Download or clone Off Grid AI Desktop from the GitHub repo.
- Install and launch it (Windows and macOS builds available).
- Open the model browser and download RealVisXL v5.0 Lightning, or grab it from Hugging Face.
- Open the image tab, select RealVisXL Lightning, and set a low step count (try 6) with low CFG.
- Type a prompt and generate. Iterate fast, save the keepers.
# Example prompt and settings
photo of a ceramic coffee mug on an oak table, morning light,
soft shadows, sharp focus
# steps: 6 cfg: 1.5
What's Coming
- More distilled few-step checkpoints in the model browser.
- Cross-device sync so renders move between your machines.
- Unified search across your generated artifacts.
The built-in model browser. Download text, vision, image, and voice models from Hugging Face, sized to your machine.
FAQ
Q: Is it really free?
Yes. The app is free and open-source under AGPL-3.0. The model is a free download. Image generation is not behind a paywall.
Q: Does it work offline?
Yes. After you download the app and the model, you can disconnect entirely. Everything runs on your device.
Q: Why so few steps?
RealVisXL Lightning is distilled for few-step generation. It reaches a finished image in roughly 4 to 8 steps, which is why it renders so quickly.
Q: How much VRAM do I need on Windows?
8 GB is the floor for SDXL. 12 GB gives you comfortable headroom.
Q: Does it run on Mac too?
Yes. The same engine runs on Metal on Apple Silicon. 16 GB unified memory is the floor.
Q: Is my data private?
Prompts and images stay on your disk. No account, no telemetry, no server we own ever sees them.
Run fast photorealistic image generation on your own hardware, for free.
