---
title: "4x-UltraSharp & RealESRGAN x4plus in ComfyUI — Folder Path, VRAM & Node Setup"
description: "How to install and run 4x-UltraSharp & RealESRGAN x4plus (ESRGAN Upscalers) in ComfyUI on Windows. Target folder: models/upscale_models/, recommended VRAM: 1 GB–2 GB (tiled)."
canonical: https://comfy.ink/models/realesrgan-x4plus
updated: 2026-10-17
---

# 4x-UltraSharp & RealESRGAN x4plus in ComfyUI

Pixel-space super-resolution models paired with tiled KSampler passes for crisp 4K output. Requires 1 GB–2 GB (tiled) VRAM and loads from models/upscale_models/.

## Facts (2026-10-17)

- **Model Family:** ESRGAN Upscalers
- **VRAM Target:** 1 GB–2 GB (tiled)
- **ComfyUI Folder:** models/upscale_models/
- **Precision:** FP16 / FP32 pth or safetensors
- **Default Sampler:** ImageUpscaleWithModel or UltimateSDUpscale

## 4x-UltraSharp & RealESRGAN x4plus Quick Reference for ComfyUI Windows

| Parameter | Recommended Setting | Notes |
| --- | --- | --- |
| Target Directory | models/upscale_models/ | Refresh canvas with R key after copying |
| VRAM Tier | 1 GB–2 GB (tiled) | Use --lowvram or GGUF Q4 on 8 GB cards |
| Weight Format | FP16 / FP32 pth or safetensors | Never load untrusted .ckpt pickle files |
| Sampler Recipe | ImageUpscaleWithModel or UltimateSDUpscale | Wire through core KSampler node |

## Where to place 4x-UltraSharp & RealESRGAN x4plus weights on Windows

Pixel-space super-resolution models paired with tiled KSampler passes for crisp 4K output.

Place the primary `.safetensors` or `.gguf` weight file inside `models/upscale_models/` inside your ComfyUI directory, or point [extra_model_paths.yaml](https://comfy.ink/install/extra-model-paths-yaml-setup) to your existing shared models drive.

After moving the file, press **R** on the [ComfyUI Studio](https://comfy.ink/studio) canvas (or click Refresh) so the loader dropdown lists the new checkpoint immediately without restarting the server.

## Recommended loader nodes and sampler settings

- **Precision & Memory:** FP16 / FP32 pth or safetensors. Cards at the lower end of 1 GB–2 GB (tiled) should pair this model with [FP8 or GGUF quantization](https://comfy.ink/words/gguf-quantization) and [VAE Decode (Tiled)](https://comfy.ink/nodes/vae-decode-encode).
- **Sampler & Scheduler:** ImageUpscaleWithModel or UltimateSDUpscale. Wire the model output into [KSampler](https://comfy.ink/nodes/ksampler) and connect the matching CLIP and VAE streams.
- **Installer:** If you have not set up the desktop environment yet, get the Windows build at [/download](https://comfy.ink/download).

## FAQ

### Which folder does 4x-UltraSharp & RealESRGAN x4plus go into in ComfyUI?

Put 4x-UltraSharp & RealESRGAN x4plus inside `models/upscale_models/` in your ComfyUI installation, then press R on the canvas to refresh node dropdowns.

### Can I run 4x-UltraSharp & RealESRGAN x4plus on an 8 GB NVIDIA GPU?

Yes — use FP8 or GGUF Q4/Q5 weights via [ComfyUI-GGUF](https://comfy.ink/nodes/gguf-loader-nodes) and keep [tiled VAE decoding](https://comfy.ink/nodes/vae-decode-encode) enabled so peak VRAM stays under 8 GB.

## Related

- [ComfyUI Models & Checkpoints](https://comfy.ink/models)
- [KSampler & KSampler (Advanced)](https://comfy.ink/nodes/ksampler)
- [Load Checkpoint (CheckpointLoaderSimple)](https://comfy.ink/nodes/load-checkpoint)
- [ComfyUI VRAM Requirements for SDXL, Flux & Video (6GB–24GB)](https://comfy.ink/guides/comfyui-vram-requirements-guide)
- [Flux.1 Dev in ComfyUI](https://comfy.ink/models/flux-1-dev)

## Download

Free desktop app: [Download Comfy](https://comfy.ink/download)

Markdown mirror: https://comfy.ink/models/realesrgan-x4plus.md