1440p and 4k streaming on amd gpu?

[lanikane]

My current pc contains an i5-9600k (not overclocked yet), a Sapphire Vega 64 Nitro+ and 32GB of ram. 1440p gaming isn't a problem, 4k depends on the game and the settings. I’ve now tried streaming using steam to a windows 10 vm running on my unraid server, but only 1080p runs ok, but not smooth... I’ve only tried CS Go and My Friend Pedro yet... I don’t think that my unraid server is the problem, since its only task is decoding the h264 stream. On the other side, CS Go is running perfectly fine even in 4k on my gaming machine. But when streaming I get only between 10-20 fps in CS Go. I’ve disabled hardware encoding, that helped a little bit but of course isn’t ideal... usually I have the IGPU disabled, but also using the Intel GPU for encoding, doesn't help... so I just want to know whether this behaviour is normal and I would just need an nvidia gpu instead (maybe because only nvidia supports framebuffer capturing?) or whether something isn’t correctly configured for example.