With no ventilation above the cpu cooler it is to be expected. Maybe try without the top lid and see the difference, if not much then double check thermal paste and cooler contact.
Thanks I will try that next. I just tested exporting a short 720p video in Shotcut and it took the temps to 90c!
This pc isn't meant for any of those tasks, primarily a HTPC but I wanted to know what its limits are. In case I wanted to do some casual gaming or similar. 90°c is insane!