"From a software perspective, an operating system and the programs you run on it tend to accumulate all sorts of cruft over extended periods of use – temporary files, disk caches, page files, open file descriptors, pipes, sockets, zombie processes, memory leaks, etc. etc. etc. All that stuff can slow down the computer, but it all goes away when you shut down or restart the system. So shutting down your computer every once in a while – and I do mean actually shutting down, not just hibernating or putting it to sleep – can give it a “fresh start” of sorts and make it seem nice and zippy again.
However, different computers and OS’s are not all equally affected by this phenomenon. Generally, a computer with a lot of RAM can go for much longer than a computer with only a little RAM. A server, on which you just start up a few programs and then let them work, will be fine for much longer than a desktop computer, where you’re constantly opening and closing different programs and doing different things with them. Plus, server operating systems are optimized for long-term use. It’s also been said that Linux and Mac OS tend to run for longer than Windows systems, although in my experience that mostly depends on what programs you use on them, and not so much on any differences between the kernels of the operating systems themselves."
Server is in a industrial environment and that means that power consumsion doesnt matter as energy hungry machines are working 24h hours per day there