[NAME] I know of no potential pitfalls, just follow the procedure, and as I noted you don't change SATA Operation in the BIOS until the middle of the procedure. I have used the procedure because I have a Samsung SSD and others in this forum have had success with the procedure. It is good that you have a  backup. Changing to AHCI will not affect your Seagate drive since I assume it is only for additional storage and does not have the operating system on it. I know of no performance/operational degradation with AHCI. 
Hi, I have a XPS 8940 which came with a WD NVMe M.5 256gb. I cloned (using Samsung data migration tool) and installed a new Samsung  970EVO PLUS 1tb in the NVMe slot on the motheboard and set aside the WD just in case ... Booted the XPS, all is working well and good. I then installed the Samsung Magician software to monitor and optimize the new drive Samsung. But Magician gives me only basic info on the NVMe ( no temperature) and does not let me optimize or update firmware. Here is the message I get : DRIVER ! Intel Corporation 17.9.1.1009 The device is connected to the driver that Magician does not support. Recommendation : Use Microsoft or Samsung NVMe driver. [IMAGE] Is there something I can do regarding the driver to make Magician do more than the basic ? Thanks
XPS 8940, New NVMe M.2 - Driver Issues