See here Roon Hardware Platform Suggestions for my experiences with a NUC with Gen3 i3 and then Gen5 i3 CPU - what you have here is Gen4 i5.
Before you start spending on a replacement with a new server or the ‘get as much horsepower as possible’ recommendations come in, see here List Your NUC Capabilities Here for benchmarked performance of a ROCK server on a NUC5i3 doing multi zone DSP just as well as a NUC7 and NUC8 unit.