Arc B580 12GB vs RX 7700 XT 12GB for Local LLMs

The Arc B580 12GB has about 6% more memory bandwidth (456 vs 432 GB/s). Batch-1 decode tracks bandwidth closely, so a model that fits both cards should decode roughly 6% faster on the Arc B580 12GB. Both fit the same number of catalog models at Q4/8K (18 of 61; 12 vs 12 GB VRAM). MSRP is $249 for the Arc B580 12GB vs $449 for the RX 7700 XT 12GB. MSRP is a launch list price, not live retail — Amazon prices move; click through for the current price. In the Q4/8K head-to-head below (40 shared models), the Arc B580 12GB posts the higher tok/s in 39 rows vs 1. Methodology.

Spec comparison

	Arc B580 12GB	RX 7700 XT 12GB
Vendor	Intel	AMD
VRAM	12 GB	12 GB
Memory type	GDDR6	GDDR6
Memory bandwidth	456 GB/s	432 GB/s
TDP	190 W	245 W
MSRP (list)	$249	$449
Buy	Search Amazon (affiliate)	Search Amazon (affiliate)

MSRP is the launch list price, not live retail. Buy links are Amazon affiliate links — the price after you click is the live price.

Q4 / 8K head-to-head — top 15 of 40 shared models

Model	Params (B)	Arc B580 12GB tok/s	Arc B580 12GB fits	RX 7700 XT 12GB tok/s	RX 7700 XT 12GB fits	Winner
Qwen3-0.6B	0.8	362.7 est.	Yes	343.6 est.	Yes	Arc B580 12GB
gemma-3-1b-it	1.0	290.2 est.	Yes	274.9 est.	Yes	Arc B580 12GB
Llama-3.2-1B-Instruct	1.2	241.8 est.	Yes	229.1 est.	Yes	Arc B580 12GB
gpt-oss-20b	21.5	180.6 est.	No	171.1 est.	No	Arc B580 12GB
Qwen3-1.7B	2.0	145.1 est.	Yes	137.5 est.	Yes	Arc B580 12GB
Qwen3-30B-A3B	30.5	117.8 est.	No	111.6 est.	No	Arc B580 12GB
Qwen3-Coder-30B-A3B-Instruct	30.5	117.8 est.	No	111.6 est.	No	Arc B580 12GB
Qwen3-30B-A3B-Instruct-2507	30.5	117.8 est.	No	111.6 est.	No	Arc B580 12GB
GLM-4.7-Flash	31.2	113.1 est.	No	107.1 est.	No	Arc B580 12GB
Llama-3.2-3B-Instruct	3.2	47.4 measured	Yes	85.9 est.	Yes	RX 7700 XT 12GB
Phi-4-mini-instruct	3.8	76.4 est.	Yes	72.3 est.	Yes	Arc B580 12GB
Phi-4-mini-reasoning	3.8	76.4 est.	Yes	72.3 est.	Yes	Arc B580 12GB
gemma-3-4b-it	4.3	74.4 est.	Yes	70.5 est.	Yes	Arc B580 12GB
Qwen3-4B-Instruct-2507	4.0	72.5 est.	Yes	68.7 est.	Yes	Arc B580 12GB
Qwen3-4B-Thinking-2507	4.0	72.5 est.	Yes	68.7 est.	Yes	Arc B580 12GB

est. = bandwidth-based estimate; measured = curated real benchmark that overrides the estimate. Fits = weights + KV(8K) + 1 GB overhead ≤ 95% of VRAM.

Fit coverage at Q4 / 8K

	Arc B580 12GB	RX 7700 XT 12GB
Catalog models that fit	18 of 61	18 of 61
Largest exclusive fit	—	—

Arc B580 12GB details → · RX 7700 XT 12GB details →