What’s the Best Way to Test a GPU Before Buying It?

The best way is to meet at the seller's place and use their PC. When I sell GPUs, I set up a system for the buyer to test it out, and I expect the same when I'm buying. If they're hesitant or make excuses, that's a red flag for me. I usually insist on testing anything over $200, but for cheaper cards, I might be less strict depending on how trustworthy they seem.

An easy way might be to ask them to record the test on their phone including a timestamp, which would give you proof that it works. I’d feel a bit suspicious if someone wanted to bring their whole setup to test the card in my place.

Definitely go to the seller’s home and test it on their setup. Running a quick stress test for about 5-10 minutes with something like FurMark should be sufficient. Once you’re satisfied, you can finalize the payment and head home.

I usually just take a low-end backup PC to test with. It's simple and effective for just checking if the card runs.

You could always rig up a portable testing setup in your car. Just use a UPS to power your PC from the trunk. It won’t give you a lot of time under load, but it should be enough to check the basic stats and do a load test.