It ran fine on my z97 classy until I added a ssd ( 950 Pro Samsung M.2 Via a four lane pcie adapter in the last slot)  I tried it in the third slot with the same results.  It will not go into 16x mode when tested.    Don't know what to do here.  first lane is set to auto and it is running in 3.0 but just won't shift up to 16x under load like it used to.  I also tried updating to the latest drivers as well. all other slots are empty.
 
help?

well isn't that just PERFECT.  SO I guess my "badass" set-up is just too weak to use just a year after i built it LOL  I get a new vid card and a new drive and now all the rest of my gear is the bottleneck..  Why then did so many people buy this expensive board for 4x sli??  the 4790K was the best at the time too. 
 
So just my card ALONE was taking up ALL of the pcie express lanes???  REALLY???  Everything else empty and I am Maxed out???
 
Seriously feeling a bit ripped off right now.  I Overbuy so I have headroom for expansion and it seems I couldn't update a single thing on this top of the line board since the day I paid for it.
 
SO now I get 1 970 ftw+  that is now cut in half to 8 lanes    and a new Drive Samsung 950 pro ssd that only takes FOUR lanes in the last slot for a total of 12 lanes. and them 4 lanes are just thrown in the trash?
 
I have 2 empty pcie slots, 1 empty msata slot AND 1 empty minipcie slot left.. That is 4 EMPTY unused slots and I am STILL Maxed out. 
 
I have to ask evga.. WHY ARE THEY THERE??

so are you saying that my new card will still run as well on 8 as it did on 16?    Also I have 4 actual lanes to spare since my pcie adapter for the m.2 only uses 4 lanes. 

 
As several people in here have mentioned, it really won't make a major difference in your speeds. Using PCIe 3.0, most cards will only lose 1-2 FPS by using an x8 slot compared to an x16.

It has to do with the 4790k only supporting 16 lanes.
970 ftw+ = 3.0 x16 (total of 16)
970 ftw+ and m2 ssd = 3.0 x8 for GPU and pcie x8 for m2 ssd (same if you're using 2-way SLI, without the m2 ssd) (total of 16)
970 ftw+ /2way SLI = First slot 3.0 =8, second slot 3.0 x8(total of 16)

And this is why I buy the E versions of CPUs and their motherboards.  I like having my 40 PCIe lanes.  I have 2 970 FTW+s running both running in 16x mode and also a sound card installed.  But I also know like others have said in the thread, there really isn't that much of performance difference.  But I like knowing that nothing is being bottlenecked by how many PCIe lanes I have.

Sorry, I think you are right. Lack of sleep, lol. I think it was AMD that could run @ x8/x4/x4.

SuperConker

NickNasc
Thanks everyone!  I was looking at having to buy a new set-up I thought.  I was hoping to hold off the new build for Pascal etc.  : ))   I am going to try disconnecting the 850 pro and running the test again.  Even Samsung can't figure out why the 850 pro and the 950 pros speeds are reversed.  It looks crazy to see the 850 at 6700 write LOL 

Sounds like you have RAPID mode enabled for your 850 Pro, that would explain the speed you are seeing.

RAPID is just a gimmick technology though, as the drive itself is really only capable of 550/520 MB/s read/write.

Yes you are right.  But still getting the slow numbers for the 950 pro and it shows I am in a proper x4 configuration : (
 
CrystalDiskMark 5.1.2 x64 (C) 2007-2016 hiyohiyo
                           Crystal Dew World : http://crystalmark.info/
-----------------------------------------------------------------------
* MB/s = 1,000,000 bytes/s [SATA/600 = 600,000,000 bytes/s]
* KB = 1000 bytes, KiB = 1024 bytes

   Sequential Read (Q= 32,T= 1) :   830.217 MB/s
  Sequential Write (Q= 32,T= 1) :   701.645 MB/s
  Random Read 4KiB (Q= 32,T= 1) :   726.326 MB/s [177325.7 IOPS]
 Random Write 4KiB (Q= 32,T= 1) :   142.097 MB/s [ 34691.7 IOPS]
         Sequential Read (T= 1) :   804.572 MB/s
        Sequential Write (T= 1) :   796.841 MB/s
   Random Read 4KiB (Q= 1,T= 1) :    56.435 MB/s [ 13778.1 IOPS]
  Random Write 4KiB (Q= 1,T= 1) :   171.109 MB/s [ 41774.7 IOPS]

  Test : 1024 MiB [C: 54.5% (259.9/476.9 GiB)] (x1)  [Interval=5 sec]
  Date : 2016/02/05 7:57:15
    OS : Windows 10 Professional [10.0 Build 10586] (x64)