RTX 3080 10GB vs RX 7900 XTX 24GB for Local LLMs

The RX 7900 XTX 24GB has about 26% more memory bandwidth (960 vs 760 GB/s). Batch-1 decode tracks bandwidth closely, so a model that fits both cards should decode roughly 26% faster on the RX 7900 XTX 24GB. The RX 7900 XTX 24GB fits more of the catalog at Q4/8K — 33 vs 17 of 61 models (24 vs 10 GB VRAM). Largest model that fits the RX 7900 XTX 24GB but not the RTX 3080 10GB: GLM-4.7-Flash (31.2B). MSRP is $699 for the RTX 3080 10GB vs $999 for the RX 7900 XTX 24GB. 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 (38 shared models), the RX 7900 XTX 24GB posts the higher tok/s in 29 rows vs 9. Methodology.

Spec comparison

	RTX 3080 10GB	RX 7900 XTX 24GB
Vendor	NVIDIA	AMD
VRAM	10 GB	24 GB
Memory type	GDDR6X	GDDR6
Memory bandwidth	760 GB/s	960 GB/s
TDP	320 W	355 W
MSRP (list)	$699	$999
Buy	Search Amazon (affiliate)	ASRock Radeon RX 7900 XTX Phantom Gaming 24GB OC (affiliate) · More listings

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 38 shared models

Model	Params (B)	RTX 3080 10GB tok/s	RTX 3080 10GB fits	RX 7900 XTX 24GB tok/s	RX 7900 XTX 24GB fits	Winner
Qwen3-0.6B	0.8	604.5 est.	Yes	763.6 est.	Yes	RX 7900 XTX 24GB
gemma-3-1b-it	1.0	483.6 est.	Yes	610.9 est.	Yes	RX 7900 XTX 24GB
Llama-3.2-1B-Instruct	1.2	403.0 est.	Yes	509.1 est.	Yes	RX 7900 XTX 24GB
Qwen3-1.7B	2.0	241.8 est.	Yes	305.5 est.	Yes	RX 7900 XTX 24GB
gpt-oss-20b	21.5	209.1 est.	No	169.7 est.	Yes	RTX 3080 10GB
Qwen3-30B-A3B	30.5	136.3 est.	No	203.6 est.	Yes	RX 7900 XTX 24GB
Qwen3-Coder-30B-A3B-Instruct	30.5	136.3 est.	No	203.6 est.	Yes	RX 7900 XTX 24GB
GLM-4.7-Flash	31.2	130.9 est.	No	203.6 est.	Yes	RX 7900 XTX 24GB
Qwen3-30B-A3B-Instruct-2507	30.5	136.3 est.	No	203.6 est.	Yes	RX 7900 XTX 24GB
Llama-3.2-3B-Instruct	3.2	151.1 est.	Yes	190.9 est.	Yes	RX 7900 XTX 24GB
Phi-4-mini-instruct	3.8	127.3 est.	Yes	160.8 est.	Yes	RX 7900 XTX 24GB
Phi-4-mini-reasoning	3.8	127.3 est.	Yes	160.8 est.	Yes	RX 7900 XTX 24GB
gemma-3-4b-it	4.3	124.0 est.	Yes	156.6 est.	Yes	RX 7900 XTX 24GB
Qwen3-4B-Instruct-2507	4.0	120.9 est.	Yes	152.7 est.	Yes	RX 7900 XTX 24GB
Qwen3-4B-Thinking-2507	4.0	120.9 est.	Yes	152.7 est.	Yes	RX 7900 XTX 24GB

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

	RTX 3080 10GB	RX 7900 XTX 24GB
Catalog models that fit	17 of 61	33 of 61
Largest exclusive fit	—	GLM-4.7-Flash (31.2B)

RTX 3080 10GB details → · RX 7900 XTX 24GB details →