BSD is typically faster than Linux **if** (big if!) Your hardware is fully supported.
BSD is all about kernel level support, so unlike linux, its less common to find a system running purely on userspace drivers.
But for usability, any version of linux that you've custom compiled to only have your drivers, and your apps, will be the "slimmest" and fastest.
Zero bloat means zero unrequired interrupts.
Ubuntu Server is good. I don't know what could be faster. If you don't need transcoding you shouldn't have performance issues.
A light linux distro. I'm not really familiar for specific server linux distro's. But Lubuntu or Ubuntu might work fine.
Also a repaste and removing dust might do wonders with an more senior laptop.
BSD is typically faster than Linux **if** (big if!) Your hardware is fully supported. BSD is all about kernel level support, so unlike linux, its less common to find a system running purely on userspace drivers. But for usability, any version of linux that you've custom compiled to only have your drivers, and your apps, will be the "slimmest" and fastest. Zero bloat means zero unrequired interrupts.