RTX 3080 10GB vs RTX 5070 12GB for Local LLMs

The RTX 3080 10GB has about 13% more memory bandwidth (760 vs 672 GB/s). Batch-1 decode tracks bandwidth closely, so a model that fits both cards should decode roughly 13% faster on the RTX 3080 10GB. The RTX 5070 12GB fits more of the catalog at Q4/8K — 18 vs 17 of 61 models (12 vs 10 GB VRAM). Largest model that fits the RTX 5070 12GB but not the RTX 3080 10GB: gemma-3-12b-it (12.2B). MSRP is $699 for the RTX 3080 10GB vs $549 for the RTX 5070 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 (38 shared models), the RTX 5070 12GB posts the higher tok/s in 22 rows vs 16. Methodology.

Spec comparison

	RTX 3080 10GB	RTX 5070 12GB
Vendor	NVIDIA	NVIDIA
VRAM	10 GB	12 GB
Memory type	GDDR6X	GDDR7
Memory bandwidth	760 GB/s	672 GB/s
TDP	320 W	250 W
MSRP (list)	$699	$549
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	RTX 5070 12GB tok/s	RTX 5070 12GB fits	Winner
Qwen3-0.6B	0.8	604.5 est.	Yes	534.5 est.	Yes	RTX 3080 10GB
gemma-3-1b-it	1.0	483.6 est.	Yes	427.6 est.	Yes	RTX 3080 10GB
Llama-3.2-1B-Instruct	1.2	403.0 est.	Yes	356.4 est.	Yes	RTX 3080 10GB
gpt-oss-20b	21.5	209.1 est.	No	266.2 est.	No	RTX 5070 12GB
Qwen3-1.7B	2.0	241.8 est.	Yes	213.8 est.	Yes	RTX 3080 10GB
Qwen3-30B-A3B	30.5	136.3 est.	No	173.6 est.	No	RTX 5070 12GB
Qwen3-Coder-30B-A3B-Instruct	30.5	136.3 est.	No	173.6 est.	No	RTX 5070 12GB
Qwen3-30B-A3B-Instruct-2507	30.5	136.3 est.	No	173.6 est.	No	RTX 5070 12GB
GLM-4.7-Flash	31.2	130.9 est.	No	166.6 est.	No	RTX 5070 12GB
Llama-3.2-3B-Instruct	3.2	151.1 est.	Yes	133.6 est.	Yes	RTX 3080 10GB
Phi-4-mini-instruct	3.8	127.3 est.	Yes	112.5 est.	Yes	RTX 3080 10GB
Phi-4-mini-reasoning	3.8	127.3 est.	Yes	112.5 est.	Yes	RTX 3080 10GB
gemma-3-4b-it	4.3	124.0 est.	Yes	109.7 est.	Yes	RTX 3080 10GB
Qwen3-4B-Instruct-2507	4.0	120.9 est.	Yes	106.9 est.	Yes	RTX 3080 10GB
Qwen3-4B-Thinking-2507	4.0	120.9 est.	Yes	106.9 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	RTX 5070 12GB
Catalog models that fit	17 of 61	18 of 61
Largest exclusive fit	—	gemma-3-12b-it (12.2B)

RTX 3080 10GB details → · RTX 5070 12GB details →