Two cards from the same 2020 generation, built on the same architecture, sit at very different prices on eBay. In our snapshot of US listings as of October 30, 2026, the median used asking price for an RTX 3090 is $1,540. For the RTX 3080 10GB it is $399. That is about 3.9 times the price.
If you only play games, almost none of that gap shows up on screen. This post looks at what the extra money buys, why the 3090 stays expensive, who should pay it, and what to check in a listing if you do.
The gap in numbers
These are median asking prices for used cards from US eBay sellers in our used GPU price index, as of October 30, 2026. They are not sold prices, and they move. Open a card's page for today's numbers.
| Card | VRAM | Used median asking price |
|---|---|---|
| RTX 3080 10GB | 10GB | $399 |
| RTX 3080 Ti | 12GB | $600 |
| RTX 3090 | 24GB | $1,540 |
| RTX 3090 Ti | 24GB | $1,775 |
| RTX 4090 | 24GB | $3,200 |
| RX 7900 XTX | 24GB | $1,150 |
| RTX 4080 | 16GB | $1,100 |
| RTX 4070 Ti Super | 16GB | $925 |
The 24GB cards stand out: the 3090, 3090 Ti, 4090 and 7900 XTX all ask more than their gaming speed alone would suggest. The 3090 Ti, which is only a modest step up from the 3090, asks about 15% more again.
What you get for gaming
Here is average frame rate at Ultra settings, rasterization only, from the Tom's Hardware GPU Benchmarks Hierarchy (dated June 2026), next to our asking prices.
| Card | 1080p | 1440p | 4K | Used asking price |
|---|---|---|---|---|
| RTX 3080 10GB | 111.6 | 82.0 | 43.9 | $399 |
| RTX 3080 Ti | 119.6 | 89.1 | 51.0 | $600 |
| RTX 3090 | 122.9 | 91.5 | 53.1 | $1,540 |
| RTX 4070 Ti Super | 141.2 | 104.0 | 58.5 | $925 |
| RTX 4080 | 157.3 | 117.5 | 67.5 | $1,100 |
| RX 7900 XTX | 161.5 | 122.3 | 70.6 | $1,150 |
| RTX 4090 | 183.6 | 143.4 | 89.1 | $3,200 |
Against the 3080, the 3090 is about 10% faster at 1080p, 12% at 1440p and 21% at 4K. The gap is widest at 4K, but you still pay roughly 3.9 times as much for it.
Now compare it with newer cards. A used RTX 4080 is about 27% faster than the 3090 at 4K and asks about 29% less. The RX 7900 XTX is about 33% faster at 4K and asks about 25% less. Both come out well ahead on frames per dollar.
Measured as dollars per average 4K frame, the 3090 comes to roughly $29, against about $9 for the 3080, $16 for the 4080 and 7900 XTX, and $36 for the 4090. Our GPU value ranking lays this out for the cards we track, and the 3090 sits near the bottom of it.
For gaming alone, the 3090 is hard to justify at this price.
Why 24GB costs so much
The 3090 has 24GB of GDDR6X. The 3080 has 10GB. Games rarely need anywhere near 24GB, so for a gamer that memory is mostly idle.
The most likely reason for the premium is demand from people who run AI models on their own machines: large language models, image generation and similar. For those workloads, VRAM capacity often decides whether a model fits at all, and speed comes second. A model that needs 20GB runs on a 24GB card and simply doesn't load on a 10GB one.
Two things make the 3090 attractive for that. It is one of the cheapest ways to get 24GB on an NVIDIA card, and a lot of AI software is written for NVIDIA's CUDA. The RX 7900 XTX also has 24GB and costs less, but it is an AMD card with no CUDA, and many AI tools either don't support it or need extra setup. For this audience the cheaper 24GB card is not the same product.
One caveat: our data shows prices, not buyers. We can't see who is purchasing these cards or why. The AI explanation is the usual one and fits the pattern, but treat it as the most likely reason, not a measured fact.
Who should buy a used 3090
It makes sense if you need the VRAM: you run local models that don't fit in 16GB, you do GPU rendering or video work with large scenes or datasets, or you want a CUDA card with 24GB and the 4090's price is out of reach. The 3090 also supports NVLink, which the 3080 doesn't, if you plan to pair two cards. If that sounds like you, a used 3090 at about half the asking price of a used 4090 is a reasonable buy.
It doesn't make sense if you mainly play games. A few better options:
- A used RTX 4080 or RX 7900 XTX is faster and cheaper.
- A used RTX 3080 10GB costs about a quarter as much as a 3090 and gets you most of the 1080p and 1440p performance.
- If you are shopping by memory size, our 12GB vs 16GB guide covers the cards in between.
What to check in a used 3090 listing
Most of the general advice in our guide to buying a used graphics card on eBay applies. A few points matter more on a 3090.
- Memory temperatures. The 3090 puts memory chips on both sides of the board, and the ones on the back are hard to cool. These cards are known for running their memory hot. Ask the seller whether they have checked memory temperatures under load, and check them yourself with monitoring software when the card arrives.
- Mining or heavy-use history. Some 3090s may have spent time in mining rigs or similar heavy use. That doesn't mean a card is bad, but it is worth asking, and a seller who answers plainly is a better sign than one who dodges.
- Memory size and model. Confirm it says 24GB and 3090, not a 3080 or a 3080 Ti with a sloppy title. Photos of the sticker on the back or a GPU-Z screenshot settle it.
- Photos of the actual card. Stock photos can't show damage, missing backplate screws or replaced thermal pads. Our eBay listing checker flags common traps on any listing you paste in.
- Test it on arrival. Run a stress test, watch temperatures, and open a return within eBay's window if the card isn't as described.
Keeping an eye on the price
Individual listings vary a lot, and asking prices move. If you decide a 3090 is worth it for your work, you don't have to check listings by hand. You can set up a free tracker for the RTX 3090 with your own maximum price and condition, and get a message when a new listing matches.