I was looking for this device on the internet and found it under the name: partilink.HG-11. It advertises that it can 1080p @ 60 fps, but it says that this is the input signal. Under resolution only says: 480p, 720p, 1080p.

So, the question would be if the output is really 60 fps or it will be down sampled to 30 fps as much cheap grabbers do.