Mac Studio M3 Ultra 96GB vs RX 7900 XT 20GB for Local LLMs

The Mac Studio M3 Ultra 96GB has about 2% more memory bandwidth (819 vs 800 GB/s). Batch-1 decode tracks bandwidth closely, so a model that fits both cards should decode roughly 2% faster on the Mac Studio M3 Ultra 96GB. The Mac Studio M3 Ultra 96GB fits more of the catalog at Q4/8K — 47 vs 32 of 61 models (96 vs 20 GB VRAM). Largest model that fits the Mac Studio M3 Ultra 96GB but not the RX 7900 XT 20GB: DeepSeek-V4-Flash (158.1B). MSRP is $3,999 for the Mac Studio M3 Ultra 96GB vs $899 for the RX 7900 XT 20GB. 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 (46 shared models), the Mac Studio M3 Ultra 96GB posts the higher tok/s in 39 rows vs 7. Methodology.

Spec comparison

	Mac Studio M3 Ultra 96GB	RX 7900 XT 20GB
Vendor	Apple	AMD
VRAM	96 GB	20 GB
Memory type	LPDDR5	GDDR6
Memory bandwidth	819 GB/s	800 GB/s
TDP	480 W	315 W
MSRP (list)	$3,999	$899
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 46 shared models

Model	Params (B)	Mac Studio M3 Ultra 96GB tok/s	Mac Studio M3 Ultra 96GB fits	RX 7900 XT 20GB tok/s	RX 7900 XT 20GB fits	Winner
Qwen3-0.6B	0.8	651.5 est.	Yes	636.4 est.	Yes	Mac Studio M3 Ultra 96GB
gemma-3-1b-it	1.0	521.2 est.	Yes	509.1 est.	Yes	Mac Studio M3 Ultra 96GB
Llama-3.2-1B-Instruct	1.2	434.3 est.	Yes	424.2 est.	Yes	Mac Studio M3 Ultra 96GB
Qwen3-1.7B	2.0	260.6 est.	Yes	254.5 est.	Yes	Mac Studio M3 Ultra 96GB
Qwen3-30B-A3B	30.5	173.7 est.	Yes	169.7 est.	Yes	Mac Studio M3 Ultra 96GB
Qwen3-Coder-30B-A3B-Instruct	30.5	173.7 est.	Yes	169.7 est.	Yes	Mac Studio M3 Ultra 96GB
GLM-4.7-Flash	31.2	173.7 est.	Yes	169.7 est.	Yes	Mac Studio M3 Ultra 96GB
Qwen3-30B-A3B-Instruct-2507	30.5	173.7 est.	Yes	169.7 est.	Yes	Mac Studio M3 Ultra 96GB
Qwen3-Next-80B-A3B-Instruct	81.3	173.7 est.	Yes	90.4 est.	No	Mac Studio M3 Ultra 96GB
Qwen3-Coder-Next	79.7	173.7 est.	Yes	93.9 est.	No	Mac Studio M3 Ultra 96GB
Llama-3.2-3B-Instruct	3.2	154.6 measured	Yes	131.2 measured	Yes	Mac Studio M3 Ultra 96GB
gpt-oss-20b	21.5	115.5 measured	Yes	141.4 est.	Yes	RX 7900 XT 20GB
Phi-4-mini-instruct	3.8	137.2 est.	Yes	134.0 est.	Yes	Mac Studio M3 Ultra 96GB
Phi-4-mini-reasoning	3.8	137.2 est.	Yes	134.0 est.	Yes	Mac Studio M3 Ultra 96GB
gemma-3-4b-it	4.3	133.6 est.	Yes	130.5 est.	Yes	Mac Studio M3 Ultra 96GB

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

	Mac Studio M3 Ultra 96GB	RX 7900 XT 20GB
Catalog models that fit	47 of 61	32 of 61
Largest exclusive fit	DeepSeek-V4-Flash (158.1B)	—

Mac Studio M3 Ultra 96GB details → · RX 7900 XT 20GB details →