@Calchalati  Furture proofing is good (for desktops) as almost every component is upgradable,  

Your processor and GPU can not be upgrade since they are soldered on the motherboard. 

I still think its' too early for Gen4 SSDs. We are yet to fully utilize Gen 3 SSDs. Yes its fun running  Crystaldismark  and seeing those high numbers. But apart from them you never see SSD being utilized that much. Again these are my personal perceptions and just recommending other users not to pay double price for Gen4 SSDs yet 

For you step 1 should be replacing the SSD you bought (if it's under warranty or return period) as dell technical support would ask for that. Once you have replaced it and issue is not resolved. You can ask for a motherboard replacement. 

It’s actually the first slot that’s NVMe Gen4, not the second.  Tested that by putting the drive on the second slot and it was running at Gen3 speeds.  

I did buy the heat shield and bracket and have that installed.  You may be right about not seeing the performance differences (yet) but I am attempting to future proof my pc as much as possible.  

I appreciate the reply but everything I am thinking is that this is software related not hardware as there are no Bios issues and the diagnostic displayed no errors.  Interestingly enough, I noticed when the drive disappears the nvm standard express controller (in windows) also disappears.  A diagnostic has showed that to fail. 

Have installed 2 NVME SSDs without fail

However I didn't overspend for a Gen 4 SSD. It's my personal perceptions that we do not have the processing power (yet) to utilize 7000 MBPS speed. 

Slot 1 had m,2 2230 by factory 

I installed a Corsair MP510 (1TB)  as secondary SSD. I am not sure which country you are in. But for India dell didn't supply SSD bracket and copper heat shield for Second SSD and I had to purchase it myself. I contacted Customer care and they informed me that SSD bracket and Shield are only supplied if I purchase dual SSD configuration  

More over the specification says 

1 Gen 3 and 1 Gen4 

However they didn't tell you which slot is gen 3 or Gen 4. I would assume second slot is Gen 4

Yep I just tried a 980 pro and it gave me extremely slow speeds at around 11 mbps.  Something is going on with this PC

Update BIOS if not updated. 

After an SSD installation RESET bios to default to get it's optimal speed. 

980 Pro should give you somewhere 3500 MBPS

Hello! I've been searching for accurate info on adding a 2nd SSD in  a G15 5511 that was only configured with 1 SSD, like the original post, and where to get the mounting hardware. 

Can all this come from Dell, or only a 3rd party? Links greatly appreciated.

I had the exact same experience. When the 980 Pro is in slot 1 (where the drive that came with the computer initially was) I only get 11MB/s read write. When the drive is in slot 2 it gets the gen 3 speeds, about 3500MB/s. Tested using the Blackmagic Design Disk Speed utility. 

The machine is on the latest firmware version (1.5.0) and Windows 10 is updated. Hopefully this can be fixed with a firmware update.

I called Dell support and they were able to look up the part numbers. Unfortunately they were out of stock on the bracket and screws. I got the 280 heat spreader from them though. It was listed on the invoice as " ASSY,BRKT,SSD,THRM,2280,SIF". The rest of the parts I found on eBay.

https://www.ebay.com/itm/304148591236

I have the same problem with a WD SN 850 in slot1(0). System have low Mb/s, USB problems and collapse by heay usage. In slot 2(1) the drive in PCIE 3.0 deliver good performance and stable in Bios 1.5

That's good to know that it is happening with a WD drive too and not just the Samsung. So it's probably not related to the drive itself but rather the computer. Anyone know if there is any way to get Dell's attention on this thread so they can get it fixed? Perhaps with a firmware update?