To clarify Tomasz' comment
That is an older U series (ie ultra-low voltage) CPU, optimized for battery life, not the computationally demanding task of real-time video encoding.
I recommend monitoring hardware resource (CPU, GPU, RAM, Disk I/O, etc) utilization [for ex. using Task manager’s Performance tab and/or Resource Monitor] to see if your system is being maxed out with your settings [which it more than likely us]. The increasing time delay Audio Processing is a common indicator of an overwhelmed system.
https://obsproject.com/wiki/General-Performance-and-Encoding-Issues and
https://obsproject.com/wiki/GPU-overload-issues
With Intel GPU, you'll want to read up on using QuickSync. To avoid (or minimize) thermal throttling, you'll want to make sure plenty of cooling (like cold air being directed at air intake, etc). Then optimize the Operating System (turning off unnecessary processes, eye candy, etc).. really streamline the system. Learn how your system responds to overheating/throttling
Oh, Do you have Win10 Game DVR=On for a reason?
Do yourself a favor, drop to 1080p30 and learn to use OBS, and don't drive blind, so to speak. Use Hardware Resource monitoring, and plan to leave plenty of headroom. That is target maybe something like a sustained 80% CPU (if your system can handle even that, it may overheat and throttle even then). You want to leave 10-20% spare headroom for the occasional/un-expected so system doesn't crash or fail to record as you are experiencing.