Just how much time/memory to you have set for the replay buffer? The replay buffer uses your system memory to store the encoding in the background. If I'm reading the logs correctly, that's 7 hours of encoded data that's being stored in RAM, which at the 90Mbps bitrate you have set for your encoder settings, that means you're trying to store 270GB of encoded video data to your memory.
You have 16GB of RAM. That means as soon as windows realizes it doesn't have enough space, it will resort to using the page file, which means it will be constantly reading/writing back and forth to your C: drive, which normally isn't a bad thing for storing video, but is absolutely horrible for operations that are expected to be dealing with RAM.
Limit your replay buffer to something that fits within the memory that you have, while allowing enough for the rest of your system to operate normally. The replay buffer isn't meant for long recording periods -- it's for short snips that happen that you want to catch immediately after they happen. If you need to record long periods, just start an actual recording session. If it turns out that you don't need something from it, delete it afterwards.
