With new GPUs selling for outrageous prices, people are looking everywhere they can to find a graphics card that doesn’t break the bank. For some, a used GPU may be the answer, but you need to take caution when considering this option.
The greatest risk when buying a used GPU is that you will get one that was used for mining. Cards used for mining are often run at full power for days, weeks, or possibly even months at a time. The constant high level of power running through the card, coupled with the taxing workload and heat, can damage the onboard circuitry and lead to the card failing far sooner than expected. This situation only gets worse if the card wasn’t kept properly ventilated, because miners often try to run as many GPUs as they can in the tightest possible spaces.
Unfortunately, it can be hard to tell if a graphics card was used for mining--in person, let alone if you’re trying to buy one from someone online--and there isn’t any real way to tell how much longer a card will last before failing. If the seller owns up to the fact that a given card was used for mining, it’s best to just walk away.
Even though miners often seek current-gen, higher-end cards, don’t assume that an older-gen used card hasn’t spent time burning up in a mining rig. Technically, it’s possible to mine cryptocurrency on a variety of desktop GPUs. Although it’s unlikely that low-end cards have been used for mining, you shouldn’t hesitate to question if the likes of an Nvidia GTX 680 or AMD Radeon 7970 is coming out of a mining rig.
If you do opt to purchase a last gen-card in hopes of saving some cash, you should also carefully consider the current price and performance of the GPU. Like newer cards, used cards have also seen an price bump due to the increased demand. For example, if you look at eBay, you can find several used GTX 980s selling for between $300 to $400. The GTX 980 competes with the GTX 1060 in terms of performance. Even if the GTX 1060 is marginally slower than the GTX 980, but they have the advantage of being new, under warranty, with more vRAM, and with lower power consumption, that makes the 1060 an overall better and safer option.
Regardless, you should evaluate the risk/reward of buying a used graphics card on a case-by-case basis, because it’s true that there may be some used graphics cards that offer you a better deal than a new one. If you do pick up a used graphics card, you should thoroughly examine and test the card immediately upon arrival to ensure it works properly (presuming you have the option of returning it if it's a dud).
If you see any discoloration on the PCB anywhere on the card, this is a clear sign that the card has been damaged by heat and shouldn’t be trusted to work long. You should also run the card through a stress test such as Furmark to see if it’s stable under full load. Some graphics cards in the early stages of failure will continue to work under a light load but fail when pushed to work at 100%. While the test is running, you should also check the fans to make sure they are spinning correctly. Make sure you check the fans during the stress test and not when the GPU is idle, however, as some GPUs turn off the fans when the GPU is idle.
If a used card passes that test, then chances are you got a functional card and likely won’t have to worry about it failing in the near future.
The last thing you want to do is spend time hunting for a deal on a used graphics card just to have it die on you a few weeks later, so take care and shop carefully.