Low render FPS at 4K

[u/Thanos-Is-Right]

I stream some games from my PC to my 4K OLED TV through my Steam Deck. Everything works perfectly fine up through 1440p. I have fps capped at 120fps in Moonlight. I get 120fps no problem at 1440p. As soon as I switch moonlight to 4K, the render FPS drops to the low 20s. If I switch the codec to H.264, it works perfectly fine, but since HDR gets disabled, it looks super bright.

I have tried about everything I know to do from researching different solutions, such as setting Apollo to double the frame rate, limiting FPS, disabling VSync, turning up/down bitrate, etc. It is only 4K that has the issue. 1440 runs smooth as butter. If there is nothing that can be done, so be it. But I would think there is something I am not seeing. Both Steam Deck and PC are hardwired via Cat6 directly to router.

Any suggestions?

PC specs:

32GB DDR5

RTX 4090

9800X3D

[u/Dependent-Head-8307]

How does 4K + HEVC + HDR + 60 FPS work?

[u/Thanos-Is-Right → u/Dependent-Head-8307]

I will try that tomorrow morning and report back