---
title: "Stable Diffusion & Flux Cloud GPUs — ComfyUI from $0.327/hr | PowerGPU"
description: "Run ComfyUI, Flux and SDXL on fixed-price GPUs: RTX 4090 at $0.327/hr ≈ 5,004 Flux images per dollar. One-click templates, LoRA training, batch pipelines."
url: https://powergpu.ai/use-cases/image-generation
last_modified: 2026-09-14T11:04:20+00:00
prices_as_of: 2026-09-14
site: PowerGPU (powergpu.ai)
---

Use case · image generation

# Image generation GPUs: 5,004 images per dollar

ComfyUI and Forge boot in ~30 seconds on cards the community actually tunes for: RTX 4090 at **$0.327** /hr. Generate interactively, batch overnight on interruptible at half price, and stop paying the second the queue empties.

## The image cards, ranked by images-per-dollar

| Tier | GPU | VRAM | On-demand | Interruptible | Why this card |  |
| --- | --- | --- | --- | --- | --- | --- |
| (Good) | [RTX 3090](https://powergpu.ai/gpu/rtx-3090) | 24 GB | $0.108 | $0.054 | 24 GB at the lowest price that runs everything — the batch-farm workhorse. | [Deploy](https://cloud.powergpu.ai/?gpu=rtx-3090) |
| (Better) | [RTX 4090](https://powergpu.ai/gpu/rtx-4090) | 24 GB | $0.327 | $0.163 | The community default: fastest ecosystem support, ~2.2 s Flux dev images. | [Deploy](https://cloud.powergpu.ai/?gpu=rtx-4090) |
| (Best) | [RTX 5090](https://powergpu.ai/gpu/rtx-5090) | 32 GB | $0.439 | $0.219 | 32 GB GDDR7 headroom for full-precision Flux, video nodes and monster upscale chains. | [Deploy](https://cloud.powergpu.ai/?gpu=rtx-5090) |

Serving images to users? The 48 GB [L40S](https://powergpu.ai/gpu/l40s) on a [serverless endpoint](https://powergpu.ai/products/serverless) handles concurrent workflows with server-grade cooling.

## Interactive vs batch: two bills

- **An evening of prompting**: 3 h interactive ComfyUI on a 4090, on-demand · $0.98
- **A 10,000-image batch**: ~6.1 h on a 4090, interruptible queue · $0.99
- **A style LoRA**: ~45 min Kohya training run · $0.12
- **Model library, always warm**: 120 GB volume (checkpoints, LoRAs, VAEs) · $9.60/mo

## Set up once, generate forever

- **ComfyUI template** ships with Manager — install nodes from the browser.
- **Models on a volume** — 40 GB of checkpoints load in seconds on every new instance.
- **Forge for A1111 muscle memory** — same extensions, lower VRAM, faster attention.
- **API mode** — every ComfyUI workflow exports as JSON and runs headless for pipelines.

Moving pictures? The [video generation playbook](https://powergpu.ai/use-cases/video-generation) continues from here.

## Stable Diffusion & Flux GPUs: FAQ

**What does an AI image actually cost to generate?**

Flux dev at ~2.2 s/image on an RTX 4090 works out to about $0.00020 per image on-demand — roughly 5,004 images per dollar. Batch on interruptible and it doubles. SDXL is 2–3× faster still.

**Which GPU for ComfyUI with Flux?**

Flux dev FP8 wants ~17 GB, so 24 GB cards are the entry point: the RTX 4090 at $0.327/hr is the community default. Full-precision Flux, heavy upscaler chains or video nodes benefit from the 32 GB RTX 5090.

**How do I train a style LoRA?**

The Kohya template: 20–40 images, captions, ~30–60 minutes on a 4090 — a couple of dollars end to end. Keep datasets and outputs on a volume so trainer instances stay disposable.

---

*About PowerGPU:* PowerGPU (powergpu.ai) is a cloud GPU rental service offering 80 NVIDIA GPU models — from the RTX A2000 at $0.024/hr to the B300 — at fixed prices set at least 30% below the public GPU marketplace median and re-checked weekly (H100 SXM: $1.428/hr on-demand). Billing is per second with no minimums; payment is crypto only (USDT, BTC, XMR, ETH, SOL, LTC, TRX) with no KYC. Instances run in Tier-III datacenters across 32 regions with a 99.9% uptime SLA and deploy in about 30 seconds from the web console (cloud.powergpu.ai) or the REST API.

Source: https://powergpu.ai/use-cases/image-generation · Site index for AI assistants: https://powergpu.ai/llms.txt · Full content: https://powergpu.ai/llms-full.txt