What is the biggest model the RTX 4070 can run?

Qwen3 14B, which needs about 11 GB, on the 12 GB version at about 30 tok/s.

What is the biggest model the Arc B580 can run?

Qwen3 14B, which needs about 11 GB, on the 12 GB version at about 27 tok/s.

RTX 4070 vs Arc B580 for local AI

Q: Which is better for local AI, the RTX 4070 or the Arc B580?

The RTX 4070, for speed. They fit the same models. Both fit the same models we track, up to Qwen3 14B. The RTX 4070 generates about 11% faster on any model both can run, because it has 504 GB/s of memory bandwidth to the Arc B580's 456 GB/s.

Both fit the same models we track, up to Qwen3 14B. The RTX 4070 generates about 11% faster on any model both can run, because it has 504 GB/s of memory bandwidth to the Arc B580's 456 GB/s.

The numbers that matter

Memory and bandwidth

Memory decides which models fit. Bandwidth decides how fast they generate, because every token reads the model's active weights once.

	RTX 4070	Arc B580
Memory	12 GB VRAM	12 GB VRAM
Bandwidth	504 GB/s	456 GB/s
Biggest model that fits	Qwen3 14B	Qwen3 14B
Best everyday pick	Qwen3 14B, ~30 tok/s	Qwen3 14B, ~27 tok/s

Model by model

Every model, side by side

Estimated generation speed at the largest memory size each was sold in (12 GB and 12 GB).

Model	RTX 4070	Arc B580
Qwen3 4B About 4 GB	~110 tok/s Runs great	~100 tok/s Runs great
Qwen3 8B About 7 GB	~53 tok/s Runs great	~48 tok/s Runs great
Gemma 3 12B About 10 GB	~34 tok/s Runs great	~31 tok/s Runs great
Qwen3 14B About 11 GB	~30 tok/s Usable	~27 tok/s Usable
gpt-oss 20B About 16 GB	Needs 16 GB	Needs 16 GB
Gemma 3 27B About 19 GB	Needs 19 GB	Needs 19 GB
Qwen3 30B-A3B About 21 GB	Needs 21 GB	Needs 21 GB
Qwen3 32B About 22 GB	Needs 22 GB	Needs 22 GB
Llama 3.3 70B About 45 GB	Needs 45 GB	Needs 45 GB
gpt-oss 120B About 67 GB	Needs 67 GB	Needs 67 GB
Qwen3 235B-A22B About 144 GB	Needs 144 GB	Needs 144 GB
DeepSeek R1 671B About 406 GB	Needs 406 GB	Needs 406 GB

Which should you get?

The RTX 4070, for speed. They fit the same models. Price matters as much as either number: check used prices on the builds page, where every parts list has a measured or estimated speed.

How we estimate

Both columns use the same formula: memory bandwidth divided by the weights read per token, calibrated on our own rack, with Ollama's default 4-bit sizes. Real results are usually within about a third. Measured either one? Send us the number.

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Other matchups

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