RTX 3080 10GB vs RX 7800 XT 16GB for Local LLMs

The RTX 3080 10GB has about 22% more memory bandwidth (760 vs 624 GB/s). Batch-1 decode tracks bandwidth closely, so a model that fits both cards should decode roughly 22% faster on the RTX 3080 10GB. The RX 7800 XT 16GB fits more of the catalog at Q4/8K — 25 vs 17 of 61 models (16 vs 10 GB VRAM). Largest model that fits the RX 7800 XT 16GB but not the RTX 3080 10GB: gpt-oss-20b (21.5B). MSRP is $699 for the RTX 3080 10GB vs $499 for the RX 7800 XT 16GB. 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 RTX 3080 10GB posts the higher tok/s in 25 rows vs 13. Methodology.

Spec comparison

	RTX 3080 10GB	RX 7800 XT 16GB
Vendor	NVIDIA	AMD
VRAM	10 GB	16 GB
Memory type	GDDR6X	GDDR6
Memory bandwidth	760 GB/s	624 GB/s
TDP	320 W	263 W
MSRP (list)	$699	$499
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 38 shared models

Model	Params (B)	RTX 3080 10GB tok/s	RTX 3080 10GB fits	RX 7800 XT 16GB tok/s	RX 7800 XT 16GB fits	Winner
Qwen3-0.6B	0.8	604.5 est.	Yes	496.4 est.	Yes	RTX 3080 10GB
gemma-3-1b-it	1.0	483.6 est.	Yes	397.1 est.	Yes	RTX 3080 10GB
Llama-3.2-1B-Instruct	1.2	403.0 est.	Yes	330.9 est.	Yes	RTX 3080 10GB
Qwen3-30B-A3B	30.5	136.3 est.	No	286.6 est.	No	RX 7800 XT 16GB
Qwen3-Coder-30B-A3B-Instruct	30.5	136.3 est.	No	286.6 est.	No	RX 7800 XT 16GB
Qwen3-30B-A3B-Instruct-2507	30.5	136.3 est.	No	286.6 est.	No	RX 7800 XT 16GB
GLM-4.7-Flash	31.2	130.9 est.	No	275.1 est.	No	RX 7800 XT 16GB
Qwen3-1.7B	2.0	241.8 est.	Yes	198.5 est.	Yes	RTX 3080 10GB
gpt-oss-20b	21.5	209.1 est.	No	110.3 est.	Yes	RTX 3080 10GB
Llama-3.2-3B-Instruct	3.2	151.1 est.	Yes	124.1 est.	Yes	RTX 3080 10GB
Phi-4-mini-instruct	3.8	127.3 est.	Yes	104.5 est.	Yes	RTX 3080 10GB
Phi-4-mini-reasoning	3.8	127.3 est.	Yes	104.5 est.	Yes	RTX 3080 10GB
gemma-3-4b-it	4.3	124.0 est.	Yes	101.8 est.	Yes	RTX 3080 10GB
Qwen3-4B-Instruct-2507	4.0	120.9 est.	Yes	99.3 est.	Yes	RTX 3080 10GB
Qwen3-4B-Thinking-2507	4.0	120.9 est.	Yes	99.3 est.	Yes	RTX 3080 10GB

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 7800 XT 16GB
Catalog models that fit	17 of 61	25 of 61
Largest exclusive fit	—	gpt-oss-20b (21.5B)

RTX 3080 10GB details → · RX 7800 XT 16GB details →