The RTX Quadro series is better, but IMO is kinda a waste right now. Pascal should be more than capable of ~10 4k transcodes, possibly more.
Use that site, there is no performance different between cards in the same generation, unless they have multiple NVENC chips (P5000). The P2000 and up support VM passthrough and unlimited transcodes natively, but both of those can be unlocked with some driver modifications. If you’re ok with 30 mins of screwing with the driver, just grab a P400.
The Turing cards (RTX) have been reported to have about double the NVENC (not sure about NVDEC) performance of Pascal, but Pascal should still be performing MUCH better than it is currently. Video memory is also somewhat important, but even my P400 seems to have no issue with 10 concurrent streams as far as video memory goes.
Its good to see that the devs are aware of the issue, aware of what is required, and actively working on it. I will definitely be willing to test out any beta/alpha versions that are available. Looking forward to a fix guys, keep up the good work!