NVIDIA RTX 4090
NVIDIA RTX 4090
In 2026, despite the 5090's launch, the RTX 4090 remains the most popular GPU on r/LocalLLaMA - and for good reason. 24 GB VRAM runs every model in the "sweet spot" range (Qwen3-30B, Mistral Small 3, Gemma 3 27B, DeepSeek Coder V3) at Q4_K_M or Q5_K_M with room for serious context. The used price has crashed to $1200-1500 since the 5090 launched.
Quick verdict
The 4090 is the answer when:
- You want the cheapest GPU that runs 30B models well
- You don't need 70B in a single GPU (use Llama 3.3 70B Q3 if you must, but it's tight)
- You're buying once and not upgrading for 3-5 years
Get a 5090 if you specifically want comfortable 70B inference. Otherwise the 4090 is 80% of the experience at 60% of the price.
Real-world AI inference
| Model | Tokens/sec | Notes |
|---|---|---|
| Qwen3-30B Q4_K_M | ~25 tok/s | Sweet spot |
| Llama 3.3 70B Q3_K_M | ~12 tok/s | Tight fit, usable |
| Mistral Small 3 Q5_K_M | ~42 tok/s | Plenty of room |
| ComfyUI SDXL (1024x1024) | ~10s/image | Excellent for image gen |
| ComfyUI Flux Dev | ~32s/image | Reasonable |
Spec breakdown
- VRAM: 24 GB GDDR6X
- Memory bandwidth: 1008 GB/s
- TDP: 450 W
- PCIe: 4.0 ×16
- Slot count: 3-slot
- Power: 850W PSU minimum, 1000W comfortable
Best models that fit
- Q4_K_M: Qwen3-30B (18GB), Mistral Small 3 (14GB) - comfortable
- Q5_K_M: Qwen3-30B (22GB) at smaller context
- Q8_0: 13-14B models like Qwen3-14B
- Llama 3.3 70B at Q3: tight but works, ~12 tok/s
Used market reality
The 5090 launch crashed used 4090 prices. Sweet spots on eBay:
- $1200-1400: well-treated cards from non-mining sources (last 18 months)
- $1000-1200: heavier-use cards, verify fans/thermals
- Under $1000: probably ex-mining, avoid unless you can verify
ALWAYS run the seller's serial through NVIDIA warranty check.
Honest alternatives
- RTX 5090 new ($2000-2200): if 70B is mandatory
- Dual RTX 3090 used build (~$1400-1800): same 48GB VRAM, worse power efficiency
- Mac Studio M4 Ultra ($4k+): bigger VRAM ceiling, slower per-token
What the community says
"Bought a used 4090 for $1300 last month after the 5090 launch. Best local AI investment I've made - Qwen3-30B at 25 tok/s is the productivity unlock I wanted."
- u/local-build on r/LocalLLaMA, 287 upvotes
Frequently asked
Quick answers to common questions
How much VRAM does the NVIDIA RTX 4090 have?
The NVIDIA RTX 4090 has 24 GB of VRAM with 1008 GB/s memory bandwidth. MSRP was $1,599.
What local AI models can run on the NVIDIA RTX 4090?
The NVIDIA RTX 4090 with 24 GB VRAM can run many models depending on quantization. Models up to ~36B params may fit at Q4_K_M. Use our VRAM calculator to check specific models.
Is the NVIDIA RTX 4090 good for local AI inference?
NVIDIA RTX 4090 is best for llm-inference, image-gen, comfyui. With ample VRAM it handles most open models well.
Where can I buy the NVIDIA RTX 4090?
Check our buy links above for the best current prices on Amazon, Newegg, and B&H. Prices vary by retailer and availability.
How does the NVIDIA RTX 4090 compare to other GPUs?
NVIDIA RTX 4090 has 24 GB VRAM and 1008 GB/s bandwidth. This puts it in the high-end category, suitable for most open models. Browse our hardware directory for side-by-side comparisons.
Is the NVIDIA RTX 4090 worth buying right now?
The current price is $1599. The price is at or above MSRP. Consider waiting for sales events like Prime Day or Black Friday.
What power supply do I need for the NVIDIA RTX 4090?
The NVIDIA RTX 4090 has a TDP of 450W. This requires a high-wattage PSU (850W+ recommended). Always check the manufacturer's recommendations for your specific build.
Nearby options
Similar hardware and models that fit
Similar hardware
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