NVIDIA GeForce RTX 4090

Verdict
The undisputed champion of consumer GPUs, offering 24GB of GDDR6X VRAM and unmatched tensor core performance for AI training and inference.
Where it wins, where it doesn't
Pros
- Unmatched raw compute
- 24GB VRAM for large batches
- Excellent software ecosystem (CUDA)
Cons
- Massive physical size
- High power draw (450W)
- Scalper pricing common
Key Features
- ✦16384 CUDA Cores
- ✦24GB GDDR6X VRAM
- ✦3rd Gen RT Cores
- ✦DLSS 3.0 Support
Specifications
| Tdp | 450W |
|---|---|
| Vram | 24GB GDDR6X |
| Cuda Cores | 16384 |
Editorial note
The 4090 remains the sensible ceiling for most people building an AI workstation, and the reason is CUDA rather than raw speed. Every framework, every tutorial, every obscure optimisation assumes NVIDIA first, and 24GB is enough for comfortable work on models up to roughly 30B quantised plus real training on smaller ones. The 5090 is faster and has more memory, but the 4090's price on the used market has made it the better value per capability for anyone not memory-bound. What you must plan for is physical: this card is enormous, it needs 450W of headroom, and it dictates your case, your cooling and probably your power supply. Check clearances before you buy, not after.
In-Depth Review
The CUDA Juggernaut
The RTX 4090 remains the holy grail for local AI practitioners who need raw CUDA compute. While Macs win on total memory capacity, NVIDIA wins on speed, software support, and ecosystem maturity.
Why 24GB matters
For fine-tuning models using LoRA or running Stable Diffusion XL, 24GB of VRAM is the sweet spot. Anything less requires heavy quantization, which degrades model output quality.
Frequently Asked Questions
Do I need a new power supply?↓
Can I fit two in a standard PC?↓
Who is NVIDIA GeForce RTX 4090 for?↓
What are the drawbacks of NVIDIA GeForce RTX 4090?↓
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What is the Fathom Layer design score for NVIDIA GeForce RTX 4090?↓
Alternatives to consider
See all alternatives →Further reading
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