RTX 4080 vs RTX 4090 — is the used flagship worth the jump?

RTX 4080 vs RTX 4090: 16GB value or 24GB ceiling?

Editorial comparison updated 2026-07-26 · live eBay medians refresh daily · Methodology

Verdict: For gaming, the used 4080 is the quiet value pick of the Ada generation: most of the 4090 experience at a much lower street price. For local AI, the fork is capability, not speed: 24GB runs 30B-class models at Q4, 16GB does not. If models are the point, pay for the 4090 (or a cheaper 3090); if 4K frames are the point, the 4080 is the smarter buy.

	RTX 4080	RTX 4090
Fair used value	$900 ($775–$1,050)	$2,325 ($1,975–$2,750)
eBay median (filtered)	$1,299 44% over fair	$3,199 38% over fair
Memory	16GB VRAM	24GB VRAM
$ / GB (at fair value)	$56	$97
Power	320W TDP	450W TDP
Launch MSRP	$1,199	$1,599

Fair values are editorial estimates; eBay medians are filtered Buy-It-Now samples, not checkout prices. See how we compute these.

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What each can run locally

Model class (weights @ Q4)	RTX 4080 · 16GB	RTX 4090 · 24GB
7–8B @ Q4 (Llama 3.1 8B, Qwen3 8B)	✓ fits	✓ fits
14B @ Q4 (DeepSeek-R1 14B distill)	✓ fits	✓ fits
30B MoE @ Q4 (Qwen3-coder 30B)	— too big	✓ fits
32B dense @ Q4 (Qwen3 32B, R1 32B)	— too big	✓ fits
70B dense @ Q4 (Llama 3.3 70B)	— too big	— too big
100B+ MoE (gpt-oss-120b class)	— too big	— too big

Approximate weights-only footprints — long context and KV cache need additional memory headroom.

The gaming case for the 4080

The 4090 is roughly a quarter to a third faster, but at 4K with DLSS both cards deliver excellent experiences — and the used price gap is far larger than the performance gap. Same generation means identical features: frame generation, FP8, AV1 encoding.

The 4080 also draws about 320W to the 4090’s 450W, with the same 12VHPWR connector caveat on both: inspect the plug on any used unit.

The AI case for the 4090

16GB runs 13–14B models with headroom and handles image generation well. 24GB is where 30B-class LLMs at Q4 become comfortable — the tier most local-AI enthusiasts actually want. There is no amount of 4080 speed that substitutes for the missing 8GB.

Note the cross-generation alternative: a used RTX 3090 carries the same 24GB for far less than a 4090, trading speed for capacity at the same ceiling.

FAQ

Is the RTX 4090 worth the extra money over the 4080?

For local AI, usually yes — 24GB versus 16GB is a capability difference, not a speed difference. For pure gaming, usually no: the 4080 delivers most of the performance at a much lower used price.

Can the RTX 4080 run 30B LLMs?

Not comfortably. 30B-class models at Q4 want roughly 19–24GB, which exceeds the 4080’s 16GB. It is excellent for 13–14B models and image generation.

RTX 4080 or 4080 Super?

They are nearly identical in practice (the Super is a few percent faster). Buy whichever is cheaper on the day — check both model pages for live medians.

Also consider

Model	Memory	Fair value	eBay median
RTX 4080 Super	16GB	$1,000	$1,360
RTX 3090	24GB	$1,200	$1,799