Its replacing my previous PC in signature. I ordered it with the following specs.
 
[<font]•750 W Platinum efficiency power supply
•WLAN RT 8822 ac 2x2 +BT 4.2LE WW
•NVIDIA® GeForce® GTX 1080Ti 11G
•Office Trial
•No Optane
•BU ICTO UMA Z370
•8th Generation Intel® Core™ i7-8700K
•Windows 10 Home
•McAfee Livesafe (30 day)
•HP USB Wired Keyboard with volume control
•32 GB memory
•512 SSD + 2 TB HDD storage
•No ODD Option
•Black Interior Paint; Side Window; External 3.5" Bay; Liquid Cooling Solution (95w Processor)
 
[<font]OTD price $2,414.99 with 4 year warranty covers support/shipping to/from and in house service. SSD is a M.2 Samsung PM961. I am seeing my GTX 1080 Ti running at PCIe X8 3.0 I cannot figure why its not running at X16 3.0 instead. I have all the newest drivers and newest bios for said machine. I was told while rare some boards will split the lanes X8/X8 for SLI which my machine can do. I had a choice to order it with SLI 1080 Ti's but chose the single card only. Which brings me back to why not the X16? The PC seems to be perfectly fine and operating like a beast other wise. I just want to make sure its okay. I have not overclocked the cpu yet. Could also this X16 issue be related to sharing lanes because of the M.2 taking 4 of them and other stuff? 
 
[<font]Picture of system here https://imgur.com/a/MJ17b
 
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Ah is this common for newer setups like mine? Or can other 8700k setups run at X16 with a M.2 ssd on board as well? I am out of the loop since the 4790k. Just want to make sure this new pc is performing as intended. 

Never really checked into it very much, but I think all M.2 runs on the PCIe bus..Myself, I would pull that M.2 SSD out just for kicks and see if it matters, even if I had to put the OS on another drive/partition for testing.

First time ever making a video. Cut me some slack!  A few goofs! https://www.youtube.com/watch?v=BZjR5pfr2BY and a follow up here https://www.youtube.com/watch?v=shLOQdIR6Lk&t
 
 
 

PCIe x8 is perfectly fine for a 1080 Ti...proven time and time again PCIe gen 3 has not been saturated enough for x16 to do much of anything within margin of error. The speed gains of your M.2 SSD would destroy any sort of theoretical performance loss (<1%) using x8 over x16 PCIe. Don't worry about it.
 
Short answer: https://youtu.be/9QG5hvy24RU?t=1124
Long answer: https://www.youtube.com/watch?v=XJuj16gRoBI

what board is in the system? depending on that is what your m.2 nvme drive will run on, for most mainstream boards the m.2 slots runs off the lanes from the chipset, the z370 in your case, and dont share lanes with the gpu from the cpu, they may share lanes with other pcie slots and/or sata ports or u.2 ports.
which slot is you gpu in? most sli boards will have a x16/x8 slot as the main and a x8 slots for the second card, they could have installed the gpu in the second slot or installed another type of card (i.e. sound card, raid card, wifi card etc..) in that second slot. if thats the case then you can move the cards around to get full x16 on the gpu. 
BTW only nvme m.2 drives run on x4 pcie, sata based m.2 run on the sata bus which might use a x1 lane depending on the board. 

Had a question for you guys. Wanted to know if this could be normal or abnormal. I was doing some very light overclocking 8700k cpu this evening using default voltage. 4.7GHz and it seemed fine. BUT when I reboot the pc would shut down for a second or 2 and then continue to start up. I cannot overclock directly from the bios as no settings exist. So my thinking is when a overclock is involved on this pc. During restart it is changing something in the bios? I don't know just a guess. Picture attached of my overclocking options. I would call it maybe a double bios post? Make any kind of sense if I am describing it properly? 
 
 

Must be the mobo or the m.2 wifi card causing it.  
 
I'm using 960 EVO m.2 NVMe SSD.

Without being privy to the documentation of the motherboard, we can’t say for sure if the rep is mistaken or if the M.2 drive results in the top slot reducing to x8 speed.

mike406
Without being privy to the documentation of the motherboard, we can’t say for sure if the rep is mistaken or if the M.2 drive results in the top slot reducing to x8 speed.

 
Funny you mention that because they really need to get their heads together over there. He mentioned PCIe lanes again and possibly just a mobo limitation. Someone else reported the exact same thing as me. They custom ordered the same machine and if this was not brand new. I would take out the M.2 ssd and M.2 wifi card just to see if those lanes open up for the card at x16. 

Pre-built is actually cheaper than doing it yourself these days.