MI300X 192GB vs RX 7700 XT 12GB for Local LLMs

The MI300X 192GB has about 1127% more memory bandwidth (5,300 vs 432 GB/s). Batch-1 decode tracks bandwidth closely, so a model that fits both cards should decode roughly 1127% faster on the MI300X 192GB. The MI300X 192GB fits more of the catalog at Q4/8K — 50 vs 18 of 61 models (192 vs 12 GB VRAM). Largest model that fits the MI300X 192GB but not the RX 7700 XT 12GB: Qwen3-235B-A22B (235.1B). MSRP is $15,000 for the MI300X 192GB 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. Not retail-shoppable: MI300X 192GB (datacenter-class; cloud rental is the realistic way to use it). In the Q4/8K head-to-head below (40 shared models), the MI300X 192GB posts the higher tok/s in 40 rows vs 0. Methodology.

Spec comparison

	MI300X 192GB	RX 7700 XT 12GB
Vendor	AMD	AMD
VRAM	192 GB	12 GB
Memory type	HBM3	GDDR6
Memory bandwidth	5,300 GB/s	432 GB/s
TDP	750 W	245 W
MSRP (list)	$15,000	$449
Buy	—	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)	MI300X 192GB tok/s	MI300X 192GB fits	RX 7700 XT 12GB tok/s	RX 7700 XT 12GB fits	Winner
Qwen3-0.6B	0.8	4215.9 est.	Yes	343.6 est.	Yes	MI300X 192GB
gemma-3-1b-it	1.0	3372.7 est.	Yes	274.9 est.	Yes	MI300X 192GB
Llama-3.2-1B-Instruct	1.2	2810.6 est.	Yes	229.1 est.	Yes	MI300X 192GB
Qwen3-1.7B	2.0	1686.4 est.	Yes	137.5 est.	Yes	MI300X 192GB
Qwen3-30B-A3B	30.5	1124.2 est.	Yes	111.6 est.	No	MI300X 192GB
Qwen3-Coder-30B-A3B-Instruct	30.5	1124.2 est.	Yes	111.6 est.	No	MI300X 192GB
GLM-4.7-Flash	31.2	1124.2 est.	Yes	107.1 est.	No	MI300X 192GB
Qwen3-30B-A3B-Instruct-2507	30.5	1124.2 est.	Yes	111.6 est.	No	MI300X 192GB
Qwen3-Next-80B-A3B-Instruct	81.3	1124.2 est.	Yes	17.6 est.	No	MI300X 192GB
Qwen3-Coder-Next	79.7	1124.2 est.	Yes	18.3 est.	No	MI300X 192GB
Llama-3.2-3B-Instruct	3.2	1054.0 est.	Yes	85.9 est.	Yes	MI300X 192GB
gpt-oss-20b	21.5	936.9 est.	Yes	171.1 est.	No	MI300X 192GB
Phi-4-mini-instruct	3.8	887.6 est.	Yes	72.3 est.	Yes	MI300X 192GB
Phi-4-mini-reasoning	3.8	887.6 est.	Yes	72.3 est.	Yes	MI300X 192GB
gemma-3-4b-it	4.3	864.8 est.	Yes	70.5 est.	Yes	MI300X 192GB

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

	MI300X 192GB	RX 7700 XT 12GB
Catalog models that fit	50 of 61	18 of 61
Largest exclusive fit	Qwen3-235B-A22B (235.1B)	—

MI300X 192GB details → · RX 7700 XT 12GB details →