Intel X series

Judging from the i9 specs and benchmarks, if gaming is your number one you would be better off z270 or Ryzen and a better GPU. I showed 750 ish 7800x ASrock CHEAP board and RAM. you could get a Ryzen 1600 setup for 400 ish. So 350 extra for the card.

I'd advise you to wait and see what the reviews say, as with Ryzen there seem to be some performance anomalies with these new CPUs, besides, the current X299 motherboards are stupidly expensive over here in the UK, decent AM4 'boards are close to half the price of the cheapest X299 parts.

Actually, looking at the numbers, it's not looking that great on the "price-to-performance" scale for these "X" chips.

In that review, for example, that i7-7900X @ stock when compared to the Ryzen 7 1800X @ stock had:
-- ~25-30% better performance in Ashes of the Singularity: Escalation (although neither one cracked 60FPS), Project CARS (although the Ryzen CPU still hit 80FPS, & the i7 barely got above 100FPS), & GTA V (conversely, both were well over 60FPS at 1080
-- ~20% better performance in Hitman (but both were over 100FPS)
-- ~5-8% better performance in Battlefield 1 (but both were over 120FPS) & Rise of the Tomb Raider (but while the i7 cracks the 144FPS barrier, the Ryzen 7 is right behind it at just under 140FPS)
-- ~2% better performance in Middle-Earth: Shadows of Mordor (but both hit over 150FPS)
-- ~1-3% lower performance in Tom Clancy's The Division (although both hit above 120FPS) & Civilization VI (although both cracked 60FPS)
-- ~12.5% lower performance in Deus Ex: Mankind Divided (the i7 wasn't quite able to crack 60FPS)

At first glance, you might say, "Hey, that i7 X chip won 7 of the 10 games, so it's a definite winner". But of those 10 games they tested, 3 of them (1 for the i7, 2 for the Ryzen) have such a small margin that I would consider them to be a tie. Of the other 8 tests, the Ashes test was significant more because it showed just how demanding that game really is (as even when overclocked & paired with a GTX 1080 Founder's Edition, that i7-7900X still couldn't quite get to 55 FPS), so even with Intel's monster CPU you have to turn down the graphics details if you want to guarantee at least 60FPS performance.

Which leaves us with 6 truly significant tests. Yes, you still have 5 wins for the i7-7900X vs. 1 for the Ryzen 7...but of those 5 wins for Intel, every single one has the Ryzen chip putting out decent performance ("decent" in this case meaning within 25% of the Intel chip and at least providing 60FPS); conversely, in the game that AMD's chip won, the Intel chip didn't quite manage to turn in a "decent" performance (i.e. it was still within 25% of the Ryzen 7's performance, but even when they OC'd the chip from 4.3GHz to 4.5GHz, it not only still didnt' make it to 60FPS, but only gained half a frame).

Which is where price-to-performance comes into play. Granted, it's hard to compare since the vendors are being really squirrelly about saying how much their X299 boards are going to cost...but I wouldn't be surprised if they end up with costs similar to the X99. Which is the problem pointed out in the article: low-end boards would be more affordable (X99 boards can run as low as $150-200USD, but the higher-end boards can run to 2 or 3 times that cost). The most expensive X370 boards for AMD can run up to $200USD, but the lower end boards or even B350 boards (which will also allow you to overclock) can be found for half the cost. With RAM, then, you're talking $250-300USD for a Ryzen build before buying your CPU (possibly as low as $200 for a low-end build), vs. probably $350-500 (or even $700) USD high-end for a Skylake-X build before buying the CPU (maybe $250-300USD for a low-end build...assuming they actually come out with any). With $450USD for the Ryzen 7 1800X & $1000USD for the i7-7900X, you're looking at:
-- Low-end ~$650USD for a Ryzen build vs. ~$1,250-1,300USD for an i7-7900X build
-- High-end ~$800USD for a Ryzen build vs. ~$1,600-1,700USD for an i7-7900X build
-- Mid-range ~700-750USD for a Ryzen build vs. $1,350-$1,500USD for an i7-7900X build

Sure, yeah, I didn't include the GPU...except that, if you plan on picking up a GTX 1080Ti for the build, you still have a situation where the Ryzen build with the 1080Ti costs as much as the i7-7900X build without the 1080Ti. Heck, even with the most expensive X370 board, you'd still be able to build the Ryzen system for less than a bottom-barrel i7-7900X system (unless you dropped the i7 build down to use a GTX 1060).

Or, to put it another way, for the cost of a Skylake-X i7-7900X system with a GTX 1080Ti...you could have a Ryzen 7 1800X system with two GTX 1080Ti in SLI, or build the Ryzen 7 system & have enough to build a halfway-decent HTPC in a mini-ITX case. When you can build 2 PCs for the price of another 1, & the main PC of the first pair can still deliver 75-80% of the performance of the other option...I'd say that it only makes sense to go for the i7-7900X if you can afford to throw $2,000USD away. I mean that literally; if your financial situation is such that you can pull a stack of 20 $100USD bills out of the bank, & run them through a paper shredder/throw them into a blazing fire/throw them out the window while driving down the freeway without suffering a heart attack (or having your family/parents/spouse/significant other threaten severe bodily harm for wasting the money so frivolously), then by all means go & buy the i7-7900X. But if (like 99% of us) you can't do that...then think twice, three times, & a whole lot of other times before buying an i7-7900X system.