RTX 3060 12GB vs RTX 4070 for local AI
Both desktop cards provide 12 GB. With the same build and context, this engine can give them the same memory-fit verdict. That does not establish equal inference speed.
Compare the right variants
GeForce RTX 3060 12GB: These results apply to the 12 GB, 192-bit desktop RTX 3060. The 8 GB desktop variant uses a 128-bit interface and requires a separate estimate; laptop capacities also differ. Manufacturer specification.
GeForce RTX 4070: Both GDDR6 and GDDR6X boards retain 12 GB. Board memory speed varies: MSI’s GDDR6 E1 example specifies 20 Gbps, while its GDDR6X Gaming Trio specifies 21 Gbps. Confirm your exact board before comparing bandwidth. Manufacturer specification.
The MSI RTX 3060 Gaming 12G specifies 15 Gbps over 192 bits: 360 GB/s theoretical bandwidth. MSI's RTX 4070 Gaming Trio specifies 21 Gbps, giving 504 GB/s over 192 bits; its GDDR6 E1 board specifies 20 Gbps, giving 480 GB/s. These are interface calculations, not measured tokens per second.
Same model, same context
Hypothetical Windows PCs: 32 GB RAM, an illustrative 8-core/16-thread CPU, 500 GB free disk, one GPU, and a working supported backend. Available RAM, free VRAM and driver version are unknown. Every build below is Q4_K_M at 4,096 tokens. Results come directly from the compatibility engine.
| Exact build | Estimated memory | GeForce RTX 3060 12GB | GeForce RTX 4070 |
|---|---|---|---|
| llama3.2:3b Build source · catalog 2026-09-13 | 2.9 GB | Excellent fit medium confidence | Excellent fit medium confidence |
| llama3.1:8b Build source · catalog 2026-09-13 | 5.8 GB | Excellent fit medium confidence | Excellent fit medium confidence |
| qwen2.5-coder:7b Build source · catalog 2026-09-13 | 5.3 GB | Excellent fit medium confidence | Excellent fit medium confidence |
| qwen2.5:14b Build source · catalog 2026-09-13 | 10.2 GB | Good fit medium confidence | Good fit medium confidence |
What would justify a speed comparison?
Measure both cards with the same model digest, quantization, runtime version, driver, context and prompt. Report prompt-processing and generation speed separately, with GPU offload, power settings and repeated runs. This site has not run that comparison, so it gives no speed ratio or purchase recommendation.
If you already own either card, start with a fitting build and use ollama ps to check where it is loaded. If a build exceeds the memory budget, switching to another 12 GB card does not add capacity; compare a smaller quantization or context first.