RTX 3090 vs RTX 4090 — VRAM & LLM Inference
24GB vs 24GB but Blackwell vs Ada. Which GPU runs more LLM models? Full breakdown.
RTX 3090 (24GB)RTX 4090 (24GB)
Feature Comparison
| Feature | RTX 3090 (24GB) | RTX 4090 (24GB) |
|---|---|---|
| VRAM | 24 GB | 24 GB |
| Memory Bandwidth | 936 GB/s | 1008 GB/s |
| Architecture | Ada Lovelace | Blackwell |
| FP16 Performance | 1,321 TFLOPS | 1,657 TFLOPS |
| Llama 3.3 70B Q4 | ❌ OOM | ❌ OOM |
| Mistral 8x22B Q4 | ❌ OOM | ❌ OOM |
| Llama 3.1 8B Q4 | ✅ Fits | ✅ Fits |
| Qwen 2.5 7B Q4 | ✅ Fits | ✅ Fits |
| Best for | Dual-GPU setups | Single-GPU inference |
| Price (used) | ~$500 | ~$1,600 |
Looking for the right GPU?
RTX 3090 (24GB)
Calculate →Consumer or data-center GPU for local LLM inference. Use our VRAM calculator to check model fit.
RTX 4090 (24GB)
Calculate →Consumer or data-center GPU for local LLM inference. Use our VRAM calculator to check model fit.
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