Can a 16 GB GPU handle a 12 GB model and still be practical? With Flux.1 on the RTX 5080, the answer is yes — but just barely. We ran the numbers on a GigaGPU dedicated server to see where the performance ceiling sits and whether the tight VRAM budget matters in practice.
Generation Speed at 1024×1024
| Metric | Value |
|---|---|
| Iterations/sec | 1.25 it/s |
| Seconds per image | 16.0 sec (20 steps) |
| Images per minute | 3.75 |
| Resolution | 1024×1024 |
| Sampler | Euler a / DPM++ 2M Karras |
| Performance rating | Good |
Benchmark conditions: 20-step generation at 1024×1024, batch size 1, FP16 precision. Using A1111 WebUI or ComfyUI backend.
VRAM Allocation and Limits
| Component | VRAM |
|---|---|
| Model weights | 12.0 GB |
| Sampling buffer | ~2.4 GB |
| Total RTX 5080 VRAM | 16 GB |
| Free headroom | ~4.0 GB |
Here is the honest trade-off: 4 GB of headroom means no ControlNet stacking, no casual resolution bumps to 2048x. For straightforward txt2img at 1024×1024, that is perfectly fine. But if your pipeline involves complex ComfyUI graphs, you will want a card with more breathing room — the RTX 3090 at 24 GB is the obvious step up.
Per-Image Costs
| Cost Metric | Value |
|---|---|
| Server cost | £0.95/hr (£189/mo) |
| Cost per 1K images | £4.22 |
| Images per £1 | 237 |
Despite the tighter VRAM, the 5080’s Blackwell architecture pushes 52% more iterations per second than the 3090. That translates to £4.22 per thousand images — nearly a pound cheaper per batch. Check our full benchmark table for the complete cost breakdown.
The Verdict
The RTX 5080 is the right Flux.1 card for teams running standard 1024×1024 generation without heavy post-processing in the pipeline. It is faster than the 3090 and cheaper per image, but the 4 GB headroom limits flexibility. For broader advice on GPU selection, see our best GPU for image generation guide and the Flux.1 hosting setup.
Quick deploy:
docker run --gpus all -p 8188:8188 ghcr.io/ai-dock/comfyui:latestRelated benchmarks: all results, Coqui TTS hosting.
Deploy Flux.1 on RTX 5080
Order this exact configuration. UK datacenter, full root access.
Order RTX 5080 Server
