More details to the quick post above.
I am not booting directly off the PCIe drive - I am booting off my old SATA SSD into Clover (r4871) and then choosing to boot off the PCIe SSD.
I can boot directly off of the PCIe drive in Windows 10 (had to install twice to get it to actually work) - but from the Windows side it does not look like Clover can boot off of the PCIe drive in BIOS mode. Some of those Windows guys are booting off a USB thumb drive into Clover, then booting the PCIe SSD. (All old posts from when the Samsung 950 was new)
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First I cloned the drive using Clonezilla (downloaded ICO, burned it with Toast, booted off of the CD), which does a byte by byte copy.
Clover didn't find the new drive. So there is a lot of things that can be done, but it looks like I needed NvmExpressDxe.efi. You can fire up Clover Configurator. Mount the EFI drive. Select the item from the Install Drivers section and download.
- Unfortunately it would download the file (where does it go?) - but couldn't move the file. Apparently v5 puts the drivers in the Drivers/UEFI or Drivers/BIOS folder in the CLOVER directory. If you create those folders by hand in an installation that doesn't have them (like my setup) - the CCv5 will install them.
- Unfortunately my setup doesn't read the drivers in those folders (I am still using an old version of Clover - r4871). You can check by looking at the Boot.log (CCv5, Boot.log, Generate log) - look for the [ LoadDrivers ] section.
- So you can put that driver in many places and it won't cause problems - narrowing it down it is happy on my machine in the drivers64 directory
Then the drive could be selected in Clover and boots. Renamed the drive to avoid confusion.
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Blackmagic gives me 696 write MB/s and 361 MB/s read on the Samsung 950 Pro 512GB.
My Crucial MX500 500GB drives connected to the internal SATA (blue port) - 256 MB/s write and 270 MB/s read
My 5TB TOSHIBA HDWE150 172 write and 173 read.
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Theoretically one could use any M.2 drive if you boot into Clover and it can support the drive. The Samsung 950 does support booting directly via BIOS, but it appears Clover doesn't like that. So, in theory, Chamelion supported OS should be able to boot directly off the PCIe card - but I don't want to go back to 10.9 and try.
I may try updating to the latest Clover on the PCIe drive and see if makes any difference - I just got this working yesterday.