From an overall quality and performance perspective, Nvidia's latest Ada Lovelace NVENC hardware comes out as the winner with AV1 as the codec of choice, but right now it's only available with GPUs that start at $799 — for the
RTX 4070 Ti. It should eventually arrive in 4060 and 4050 variants, and those are already shipping in laptops, though there's an important caveat: the 40-series cards with 12GB or more VRAM have dual NVENC blocks, while the other models will only have a single encoder block, which could mean about half the performance compared to our tests here.
Right behind Nvidia in terms of quality and performance, at least as far as video encoding is concerned, Intel's Arc GPUs are also great for streaming purposes. They actually have higher quality results with HEVC than AV1, basically matching Nvidia's 40-series. You can also use them for archiving, sure, but that's likely not the key draw. Nvidia definitely supports more options for tuning, however, and seems to be getting more software support as well.
AMD's GPUs meanwhile continue to lag behind their competition. The RDNA 3-based RX 7900 cards deliver the highest-quality encodes we've seen from an AMD GPU to date, but that's not saying a lot. In fact, at least with the current version of ffmpeg, quality and performance are about on par with what you could get from a GTX 10-series GPU back in 2016 — except without AV1 support, naturally, since that wasn't a thing back then.