Macs don't support Intel PCIe Lane Partition at all, aka bifurcation. Asus Hyper M.2 x16 GEN4 still requires it.
Read the first post of the thread:
This is a general info thread for blade SSDs that can be used in the Mac Pro. This is a WikiPost so anyone with the proper credentials may edit it. NVMe SSDs can be used as a boot drive in the MP5,1 and MP6,1 with the latest firmware installed (beginning with version 140.0.0.0.0 for MP5,1 and...
forums.macrumors.com
New to the Forum. I have zero experience with Macs (technically) and only got into building PCs to test configurations for my own startup software business in late 90's. I know enough to figure stuff out, but not explain it. My kids got me into Apple - I am a big fiscal supporter now. As we get older, they 'just work' which I like about Apple quality. I don't like the price tags.
I only use Macs for basic computing. I recently got into drones and videos so upgraded 2013 MBP with NVMe SSD - and can run full video editing on an Intel Iris 4000 card as a result. It isn't a powerhouse for video, but decent results and reasonably keeps up with the new MBP with dual AMD 5500.
So, I recently bought a base cMP 4,1 (2009) in perfect shape for $500 as a project to make into usable storage and video editing machine, through upgrades. Incredible quality build in the cMP, especially compared to days of PCs! Fun of the project is to not to exceed $1000 CDN.
I took the machine back to basics, cleaned/dusted and wiped everything and started from there. So far,
> flashed to 5,1 firmware
> added an 120GB SSD boot drive (had)
> kept 640 Apple original SATA (came with)
> running MacOS 10.15.7 (Opencore)
> the added 2 x 1TB SATA ($20 each) for storage in RAID-0
> kept DVD drive
> RX580 bought (waiting for the added power cables) so running gt120 still
Keeping to the fiscal restraint, I bought new ASUS Hyper M.2 x16 Card V2 for $60, new WD Black SN750 - 500GB (full price $100 taxes in) to put in. I figured the ASUS card would work, and liked that the card had a large heat sink and switchable fan. Ok, the $60 price tag, same day, no Amazon, was a attractive too. Then, I get into the Forum and was thinking the Project was out $60 after reading a number of the threads.
Nonetheless, I owned it now so I popped in the NVMe into the ASUS (great build quality) and popped into slot 2 (the x16) and fired up the Pro. Upon log in, I received an error message window that the 'storage media is not recognized' and gave me an option button to initialize. I restarted and same thing but still could not see it in the Finder window and nothing after clicking 'initialize'.
Opening System Report, and it showed up under the NMVExpress and PCI, generic, but there. So I opened up Disk Utility, clicked Show All under the View Menu tab and there it was! Uninitialled and just waiting to be formatted! Quick format and showed up under Finder.
So, I can say I have a stable operating ASUS Hyper M.2 x16 Card V2 working in 4,1 flashed to 5,1 running Catalina. It appears as an internal drive.
My speeds are in the mid 750's using Disk Speed Test (BlackMagic) so I know I have to work on getting the lane issue (assumed) figured out as that is well below the theoretical speeds I expected as the Black Magic is capable of 3420 MB/s speeds, just don't know if the cMP is via PCIe 2.0.
I will update if I can get the speeds up.