Hi everybody,
I can confirm what scarr500 is writing. I managed to install Windows 7 Pro 64 on the Samsung 950 Pro ssd on a HP Z820 and all works well. Benchmarks are a little slower than expected bur overall everything reacts very fast. The 950 Pro is in a PCI-e slot with the help of an adapter card, (http://www.addonics.com/products/adm2nvmpx4.php)
What I did;
I first updated the bios to 3.88
I copied the whole content of the HP Win 7 Pro DVD to a folder on the harddisk of my second pc. I changed some folders and added the bootmgfw.efi file wich I found in the folder C:\Windows\Boot\EFI on my second pc, (wich has Win 7 Pro). I changed the name from bootmgfw.efi to bootx64.efi and copied it to the right folder of the copied HP Install disk on my second pc. For details, check step 11 on this website; http://www.eightforums.com/tutorials/15458-uefi-bootable-usb-flash-drive-create-windows.html
Now I created an EFI bootable Windows 7 Pro 64 install disk from an original HP win 7 install disk.
Than I created a 8 GB bootable USB stick with diskpart as described in option two on the website mentoned above.
I copied the whole content of the (now EFI bootable) install disk from the folder of my second pc to a 8 GB bootable USB stick and added a folder with the Samsung Nvme drivers. Not the .exe driver but the seperated 4 driver files including the .inf file. They can be found here;
https://mega.nz/#!BMkTTIYT!eGkmAYmjIHjtFChQ635ySy1P1f5MA9w2u_sXyIM9TBw
Than I booted up the HP Z820 from the USB stick in UEFI mode. With F6 I loaded the Samsing drivers and the 950 Pro SSD was recognized by Windows. I wiped all partititions and made new ones, which will be GPT partitions, automatically made by Windows. Than I proceeded installing Windows.
Disconnect all other drives apart from the 950 Pro before installing. In the BIOS secure boot must be disabled.
Good luck!
