What is a good way to benchmark test a GPU in Linux?

Edit: I was able to run some benchmark tests, so I don't need help with this anymore, but after running the tests, I'm pretty sure my computer is having hardware issues. I don't really have any other options, though, so I just have to deal with it.

The computer I was using stopped working and I had to switch to a different computer but despite having a significantly better GPU, games are performing only slightly better. I want to benchmark test the GPU to see if it's a potential hardware problem or if something else is causing a bottleneck.