yes, the SSD GAMMIX S70 runs okay know in gen3 slot... but no in his full velocity (7000mb-s)... only 3500mb-s

Hi @EIRASFE welcome to this free user to user Alienware laptop discussion forum. 

Yes, the m15 R6 SDD slots are the problem. 

XPG says their M.2 2280 SSD GAMMIX S70 Blade is a PCIe Gen4.0 x4 NVMe card and it is backward compatible with PCIe Gen3.0 x4 NVMe slots. XPG Gaming GAMMIX S70 BLADE PCIe M.2 NVMe SSD｜XPG 

Support forAlienware m15 R6, Setup and Specifications, Storage says its M.2 SSD PCIe Gen3.0 x4 NVMe slots will only run at up to 32 Gbps. Dell Documentation Storage does not include slot identification, usually SSD-1 and SSD-2. See Service Manual Solid-state drive. 

Dell knows that their documentation requires clarification. @DELL-Cares 

Hi @EIRASFE which slot accepts your 2TB M.2 PCIe Gen4.0 x4 NVMe card? 

Alienware m15 R6 slot SSD1Alienware m15 R6 slot SSD2

SSD1 slot is the Gen4.

When i pluged my SSD in SSD1 slot, the velocity runs full...  6000 - 6800mb-s. But then becomes instable and the velocity come to 100 mb-s and then the SSD became offline.

When i pluged my SSD in SSD2 slot, theres no error. But the velocity runs ate 3500 mb-s.

I have a similar issue. I bought WD SN850 2TB, and when I installed it on Slot 1 in my M15R6, although it can run with the speed of 7000MB, the system became unstable. Always restart with the blue screen. Then I installed WIN 11 in PM9A1 on Slot 2, then I found the SN850 on Slot 1 would disappear randomly. You have to restart the PC to have the SN850 back. So I have to switch these two SSD. PM9A1 on Slot 1 with Gen3, then no blue screen again. I feel so bad, if Slot 1 can not support Gen4, Dell should modify the user manual.

Same to you

I had the same problem.
Even updating the BIOS didn't fix it.
I didn't find any information that solved it.
When I use M.2 gen 4 on SSD1 the speed drops to 100MB/s and the HD disappears.

Hi @EIRASFE the Alienware m15 R6 Drivers & Downloads has many extra drivers to get SSD1 to acknowledge that this M.2 slot is PCIe Gen4x4 capable.

The XPG ADATA SSD ToolBox is available for download with the XPG GAMMIX S70 BLADE PCIe Gen4x4 M.2 2280 SSD card. The ADATA SSD ToolBox automatically ensures you have the latest firmware for optimal performance and allows for the monitoring of drive health and remaining life through Self-Monitoring, Analysis, and Reporting Technology (S.M.A.R.T.) attributes. It also lets you keep track of the current operating temperature, capacity, and total space used. 

Please download the ADATA SSD ToolBox and run the Diagnostics, etc. to determine if the 2TB XPG S70 Blade requires a driver firmware update.  

The Crystal Disk Info x64 utility has more diagnostic options. Crystal Dew World [en] - (crystalmark.info) 

Did you check the Gen4 drive temperature? 

I have the same problem and the high temperature is the cause.

When I run games on my Samsung 980 PRO 2 TB... the system becomes unstable and crashes. Even with heat sinks and a cooled base.

The default heatsinks cannot dissipate the heat generated by the drives. My solution for this was a Gen3 drive, and I've no more problems.Gen3 drives generate less heat. My Gen4 drive runs only windows and other software, so the drive is under a low load generating less heat.

I have R6 and R7 and both have the same issue with high loads on disks Gen4.

Hi everyone,

im having the same issue as above, huge disappointment and lot of time wasted.
i have m15 R6(i7-11800H/RTX 3070 version), i have ordered kingston KC3000 PCIe gen4 about a week ago, with the hope(again, it is written in the user manual that it DOES support gen4...all of us should guess it can run games right? not in idle state of windows....) i can enable its performance in slot0 and keep my factory provided micron 2300 into slot1 as a DATA drive. everything went fine(both drives recognized, kingston performed gen4 speed as described) until i tried some programs requiring  high performance.
system became unstable, random BSOD's, random freezes/force restarts during games, even during downloads at higher speeds.... i have gone through the error-discovery process, searching/scanning for hardware issues via supportassist/various 3rd party softwares, nothing turned up. then i tried to switch up the SSDs in the 2 slots, same issue. tried to use KC3000 alone(micron 2300 removed from slot1), still random BSOD's...
now its more than enough, im returning KC3000 with money back and looking for a gen3 drive which hopefully won't cause issues on the system...
anyone even running 2 gen3 SSD's in the same model without issues or i should forget about the second slot and rather use external drive?