I've replaced the fan, and it's running OK now and the temps are normal. However the box is doing some thumbnail creation (weirdly called converting) on the 25000+ images I've got in there. Looking on Synology's forum it's cos of the pre-installed image software and it'll go and create a separate thumbnail for each picture. I've tried disabling the software, but the process stubbornly refuses to stop. It's not really a problem, but it's pegging the CPU at 99% and it looks like it's going to take a few days to finish.
EDITED: 1 Mar 2017 09:06 by GRAPHITONE