How to make a picture in maximum quality on an existing processor?

Question

Nginx

Hello. I do streaming. Decided to make a restream server. I built a separate machine on Linux. 2x Xeon 2620 each 6 cores 12 threads. RAM 16 gigs.

nginx.conf

worker_processes 22;
worker_rlimit_nofile 400000;
worker_priority -19;

events {
worker_connections 8192;
use epoll;
multi_accept on;
}

rtmp_auto_push on;
rtmp {
server {
listen 1935;
max_message 10M;
chunk_size 8192;
....
# EWOWKO1241_________________________________________________________________________________

application ewowko1241<---->{
live on;
record off;

exec ffmpeg -re -i rtmp://127.0.0.1/ewowko1241 -vcodec libx264 -g 60 -preset medium -profile high -b:v 7750k -maxrate 7750k -bufsize 7750k -s 1920x1080 -x264opts nal-hrd=cbr:force -cfr=1:keyint=120:scenecut=60 -sws_flags lanczos-acodec copy -r 60 -f flv rtmp://127.0.0.1:1935/transcode_ewowko;
........
push rtmp:// service to which the stream is simply copied;
<------>
<------> }
........
application transcode_ewowko1241 {
live on;
meta copy;
<------>
push rtmp:// service with transcoding;

....

<------>
<------> }
}
}.

I will send a stream from the OBS program 50 Mbps. The card is falling off. Processor load 75% Reduced the flow to 30 Mbps, the picture periodically pours. Square color artifacts. On complex dynamic scenes. I tried the fast ultrafa presets, the main high profile, everything that can be changed did not solve the problem. I would like to squeeze the processor to the maximum and get the best possible picture without artifacts at 8Mbps. So there is a problem with the video delay. It is about 7-10 seconds. the -zero latency command crumbles the picture at a bitrate of 30 Mbps. On Windows, I tried the medium profile, the picture did not crash. What could be the problem?
CPU load. On the screen, there is practically no peak anymore.

The computers are connected by a 1Gbps network.
An example of which I managed to hide. True, the gray picture is not entirely clear. On the colored squares are colored.

Answer 1

I will send a stream from the OBS program 50 Mbps.

Streaming in 8k? Otherwise, I don’t understand why the stream is 50Mbps, for full HD, 3-5Mbps is more than enough.
Transcoding is better done on the GPU, not the CPU