I would advise against building a gaming computer right before the 14nm GPU node products are released here in a few months.
You'll always be waiting for something. The 14nm GPUs. They'll arrive and it'll be 10nm canyon lake chips. DDR5 memory. It is a never ending game. Just fucking buy something. You are building a computer today.
Also, note Intel stepped off Moore's law in early 2004 when they hit the powerwall.
http://www.edwardbosworth.com/My5155_Slides/Chapter01/ThePowerWall.htmThey are about to hit the infrastructure size wall. 14nm was a watershed moment in electronics. It was the first time in history that it cost more money to have the same amount of transistors on a subsequent chip. IE chips from 14nm onwards will give less bang per buck.
This from an industry that used to give us 50% increase on a processor ever year. We are now down to about 5% and have been since 2008.
When I was at uni, you'd build another PC every 2 years - 3 years ... you had to. Software made your machine obsolete and the next gen was always so much better. Now a PC from 2008 still runs absolutely fine.
Paying £100's more for a teeny bit of perceived performance which is mostly benchmark fap material and not worth it in the real world is silly.
Ok, so you need more ammo to ridicule my post ... here's my suggestion.
You aren't afraid of linux like me. You need a games machine. You really don't need bleeding edge shit. Does it really need to be a massive noisy lump under your desk? Get something small, quiet and pretty.
http://www.dell.com/uk/p/alienware-steam-machine/pd?oc=d00asm08&model_id=alienware-steam-machineThe processor is 4th gen. This is good. 6th gen has had all kinds of driver issues. 14nm is a bollocks. However the passmark score of the i7-4785T is 7485 and of the i5-6600k you choose is 7803. There is sod all in it.
http://www.cpubenchmark.net/compare.php?cmp%5B%5D=2260&cmp%5B%5D=2570But the i5 is going to cost way more because it is 6th gen. Also note the i7-4785T is a T. IE only 35W compared with the massive 95W of the PC you are looking at. That translates to a massive amount of heat and hence fan noise - especially if they are overclocking it for you for the sake of another 10% performance .... that processor isn't going to be your bottleneck on £1000 machine. That'll get annoying.
A complete machine, and you still have a staggering £300 left over to buy cool games, a better sound system, treat yourself to a monitor, buy more game pads, external storage drives, whatever you like.
Get a steam machine, pay £0 for the OS, its slightly older gen giving you great value for roughly same performance, quiet, cheaper, looks nice, sits under your TV fine, has controllers ... boom ... Thork to the rescue ... again. They do the alpha if you want a windows version of the same machine. G
Otherwise check out Quiet PC ... they build solid PCs with no bloatware for a good price.
https://www.quietpc.com/systems