I've been using my Z87 / 4770k system for quite a while, and while it would still meet most of my needs I wanted something new. While playing games I didn't mind the sound that my "White Devil" produced. However I use my machine alot more for work now than playing games and the sound is annoying. I found myself listening to music just to drown out the fans.
For work and hobbies other than gaming high IO is handy. I have a server rack in my basement and have decent storage but I'm considering selling that and moving to a newer NAS connected via thunderbolt or usb type c.
This led me to the motherboard for this build. As of the time of my build it is the only unit rated at 40GBPS available for a decent price.
I went with the 5820k as unless I jump up to the 8 core, with a bit of overclocking its right on par with a 6800k.
Now that I have built this and with Overwatch getting a decent amount of my time, I plan on getting a GTX 1080 as soon as availability calms down.
Oh also I swapped out the 3pin NZXT fans for some 4pin units left over from another build. This allows me to control all the fans (sans GPU) from the utility that runs the X61 and the result is a nearly silent computer for working and something that can play games without a ton of noise either.
Currently it is running at 4.5ghz @ 1.3 volts. with the XMP profile from the ram. Was stable enough (8+ hours of gameplay so far) but I do still plan on doing some more tweaking when time allows.