In this guide you will learn:
- →Install ComfyUI on Windows from scratch
- →Configure Python, CUDA, and PyTorch correctly
- →Launch with GPU-optimized flags for your VRAM
- →Install and manage custom nodes via ComfyUI Manager
- →Run your first SDXL workflow in under 30 minutes
- →Read benchmarks for RTX 5080, 4090, and 3080
ComfyUI Complete Setup: RTX 5080 Edition
ComfyUI is the most powerful node-based interface for running local AI image and video generation. This guide gets you from zero to a working workflow on Windows with an NVIDIA GPU — tested live on an RTX 5080 and RTX 3080 16GB.
:::stats :::stat 16GB | VRAM Required :::stat 12 min | Setup Time :::stat 3.2s | SDXL per image :::stat Free | Open Source :::
#Hardware Requirements
| GPU | VRAM | Best Use Case |
|---|---|---|
| RTX 5080 | 16GB | Full quality, all models, fast batch |
| RTX 4090 | 24GB | Full quality, FLUX FP16, large batch |
| RTX 3080 16GB | 16GB | Full quality, slower on large models |
| RTX 3080 10GB | 10GB | Reduced resolution, GGUF models |
| RTX 3060 | 12GB | Standard models, SD1.5 and SDXL |
| GTX 1660 Ti | 6GB | SD1.5 only, very slow |
:::note Minimum Requirements 6GB VRAM for SD1.5. FLUX and LTX Video require at least 12GB. For best results with modern models, 16GB is the sweet spot. :::
#Step 1 — Install Prerequisites
You need three things before cloning ComfyUI: Python 3.10, Git, and the CUDA Toolkit.
Python 3.10.x
Download from python.org — use exactly 3.10.x, not 3.11 or 3.12. Many custom nodes have dependency conflicts with newer versions.
:::warning Version matters Do NOT install Python 3.11 or 3.12. Custom nodes like AnimateDiff and VideoHelperSuite require 3.10.x. Using a newer version will cause cryptic import errors. :::
Git
CUDA Toolkit
Download CUDA 12.1 from nvidia.com/cuda-downloads. Match your driver version.
#Step 2 — Clone ComfyUI
:::tip Keep it at C:\ComfyUI Installing at the root avoids Windows path length issues that break certain custom node installs. Deeply nested paths cause silent failures. :::
#Step 3 — Install Dependencies
The PyTorch install will download ~2.5GB. This is the step most people mess up — make sure you're using the cu121 index URL, not the default PyPI version.
#Step 4 — Install ComfyUI Manager
ComfyUI Manager adds a one-click node installer directly inside the UI. It's essential.
After this, every time you find a workflow that needs missing nodes, ComfyUI Manager will detect and install them automatically.
:::pro Install Order Install Manager BEFORE downloading any models. When you load a workflow that requires missing custom nodes, Manager will prompt you to install them all at once. :::
#Step 5 — Download Your First Model
Place models in ComfyUI/models/checkpoints/
Recommended starter:
For FLUX (requires 12GB+ VRAM):
#Step 6 — Launch ComfyUI
Open your browser to: http://127.0.0.1:8188
:::note Bookmark this URL
ComfyUI runs as a local server. Bookmark 127.0.0.1:8188 — it's faster than typing it each time.
:::
#RTX 5080 Optimal Settings
These settings max out quality on 16GB VRAM with headroom for LoRAs:
#Installing Essential Custom Nodes
In ComfyUI Manager, search and install these first:
- →ComfyUI-Impact-Pack — face detailing, segmentation, upscaling
- →ComfyUI_IPAdapter_plus — image prompt control
- →ComfyUI-AnimateDiff-Evolved — video animation
- →ComfyUI-VideoHelperSuite — video input/output (required for LTX)
- →rgthree-comfy — better node organization and groups
#Your First Workflow
- →Click Load in the top menu
- →Select
default_workflow.json - →In the
Load Checkpointnode, select your downloaded model - →Click Queue Prompt
You should see your first image in 15–30 seconds on an RTX 5080.
:::tip Speed up iteration While testing prompts, use batch size 1 and 15 steps. Once you find a direction you like, bump to 25 steps and batch 4 for the final run. :::
#Performance Benchmarks
Tested on RTX 5080 16GB, --gpu-only --highvram:
| Model | Resolution | Steps | Time |
|---|---|---|---|
| SDXL FP16 | 1024×1024 | 20 | ~3.2s |
| FLUX Dev FP8 | 1024×1024 | 20 | ~8.1s |
| SD 1.5 | 512×512 | 20 | ~0.8s |
| LTX Video 2.3 | 768×512 97f | 25 | ~5.4s |
:::stats :::stat 3.2s | SDXL per image :::stat 8.1s | FLUX Dev FP8 :::stat 5.4s | LTX Video clip :::stat 0.8s | SD 1.5 image :::
#Common Issues
"CUDA out of memory" — Add --lowvram to launch command, reduce batch size to 1, or switch to a GGUF quantized model.
Black images — Your VAE doesn't match the model. Download the correct VAE for your checkpoint and load it manually with a VAELoader node.
Slow generation — Check --gpu-only flag is set and your venv is activated. Without the venv, you'll use the system Python and possibly CPU inference.
Nodes missing — Open ComfyUI Manager → click "Install Missing Custom Nodes". This auto-detects and installs everything a workflow needs.
You're ready to run your first workflow. Next up — training your own LoRA to lock a character or style into any model.