RTX 5090 vs RTX 4090: the next leap in AI GPU performance

Ana Pace

August 12, 2025

At 1Legion, we’re always looking ahead — because the future of computing doesn’t wait. The launch of the NVIDIA RTX 5090 marks one of the most significant leaps in GPU technology since the arrival of the RTX 4090. And for AI, machine learning, and high-performance computing (HPC), the difference isn’t just about bigger numbers on a spec sheet — it’s about unlocking new possibilities.

Why the RTX 5090 Changes the Game

When the RTX 4090 arrived, it set a new standard for AI workloads, large language model (LLM) inference, and high-resolution rendering. The RTX 5090 takes that foundation and pushes it even further, delivering:

  • Massive Throughput Gains – In LLM benchmarks, the 5090 consistently outpaces the 4090, handling larger batch sizes and delivering faster inference times.
  • Higher Memory Bandwidth & Capacity – With increased VRAM and bandwidth, the 5090 can process more data per second, reducing bottlenecks in AI training and inference.
  • Better Efficiency – Architectural improvements mean you can get more performance per watt, which matters when scaling workloads in the cloud or on-prem.

In short: more speed, more headroom, and more efficiency — exactly what next-gen AI workloads demand.

LLM & AI Benchmark Insights

Recent benchmarks show the RTX 5090 delivering up to 40% faster inference on popular LLMs compared to the 4090. For model training, that means fewer hours to converge; for real-time inference, it means lower latency and more simultaneous requests served.

Figure 1 – RTX 5090 vs. RTX 4090 LLM Inference Benchmarks
In side-by-side tests, the RTX 5090 consistently outperformed the RTX 4090 across multiple large language models, delivering up to 40% faster inference times and supporting significantly larger batch sizes without VRAM bottlenecks. This translates into faster training cycles, smoother scaling, and the ability to serve more concurrent requests — a key advantage for demanding AI workloads.

For example:

  • 4090: Solid performance for models up to 70B parameters, but may need batching strategies for ultra-large deployments.
  • 5090: Handles massive models and batch sizes with ease, offering smoother scaling without hitting memory limits as quickly.

If your work involves LLM fine-tuning, multi-modal AI, or heavy-duty simulation, this difference translates directly into time saved — and more experiments run per week.

Choosing Between the RTX 4090 and 5090

The RTX 4090 remains an incredible GPU and delivers strong value for many workloads. If your models fit comfortably within its VRAM limits and you’re not pushing extreme batch sizes, it’s still a powerful choice.

However, the RTX 5090 is built for those pushing boundaries:

  • Training larger or more complex models
  • Running ultra-low latency inference at scale
  • Preparing for next-gen AI frameworks and toolchains

For teams working at the edge of AI’s capabilities, the 5090’s additional performance is not just a luxury — it’s a competitive advantage.

Access the RTX 5090 at 1Legion

You don’t need to invest in costly on-premise hardware to harness the 5090’s power. At 1Legion, we make it available on demand — so you can train, fine-tune, and deploy without the wait or upfront expense.

Whether you choose the RTX 4090 for balanced performance or the RTX 5090 for bleeding-edge speed, you’ll get:

  • Flexible scaling to match your workload
  • Top-tier infrastructure optimized for AI and HPC
  • Instant availability so you can focus on innovation

Contact our Engineers here and start your journey with 1Legion

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