MP All Models PCIe SSDs - NVMe & AHCI

[SorpassoSonance]

You can double that speed with a PCIe card (Sonnet Tempo / OWC Accelsior) for your SATA SSD’s.
This produces a SATA 3 interface.

If I put a Samsung Evo 860 2 TB 2.5" SSD into the OWC Accelsior S 2.5" to PCIe adapter, will Monterey installed via Martin Lo's 1.0.1 package be bootable with it?

Going from 250 mb/s to 500 mb/s sounds nice. I don't know if I'll have room for the Accelsior S, though; I'll have a Gigabyte 5700 XT taking up the two bottom slots and then a kryoM.2 PCIe adapter + heatsink with a WD SN750 in it occupying slot 3. Dunno if there will be enough room above the kryoM.2 adapter for the Accelsior S to fit, or even if it does if that would be advisable in terms of thermals.

Mac Sound Solution has also pointed out in some of his videos on the Mac Pro 5,1 that when you turn the computer on it checks bay 1 first in terms of trying to find a boot drive, so having a 2.5" SSD in bay 1 via an OWC Mount Pro 2.5" sled will lead to the fastest boot time simply because the machine checks bay 1 before it does any of the other bays or PCIe slots. Of course you're getting 250 mb/s max speed then instead of 500 mb/s, but if one isn't transferring large files very often it might indeed be preferable to have the slightly faster boot time.

 

[basslik]

If I put a Samsung Evo 860 2 TB 2.5" SSD into the OWC Accelsior S 2.5" to PCIe adapter, will Monterey installed via Martin Lo's 1.0.1 package be bootable with it?

Going from 250 mb/s to 500 mb/s sounds nice. I don't know if I'll have room for the Accelsior S, though; I'll have a Gigabyte 5700 XT taking up the two bottom slots and then a kryoM.2 PCIe adapter + heatsink with a WD SN750 in it occupying slot 3. Dunno if there will be enough room above the kryoM.2 adapter for the Accelsior S to fit, or even if it does if that would be advisable in terms of thermals.

Mac Sound Solution has also pointed out in some of his videos on the Mac Pro 5,1 that when you turn the computer on it checks bay 1 first in terms of trying to find a boot drive, so having a 2.5" SSD in bay 1 via an OWC Mount Pro 2.5" sled will lead to the fastest boot time simply because the machine checks bay 1 before it does any of the other bays or PCIe slots. Of course you're getting 250 mb/s max speed then instead of 500 mb/s, but if one isn't transferring large files very often it might indeed be preferable to have the slightly faster boot time.

There's really no noticeable difference on boot up times, even though it checks bay 1 first.

Forget 250/500. Go all NVMe *SPEED*! 1,500MB / 3,000MB. I only use the bays for backups to SSD's. slot 3, OS drive, slot 2, working highpoint dual drive, slot 4 for samples. ( NEED FOR SPEED )

 

[SorpassoSonance]

1/17/26 edit: seems like no major manufacturers make PCIe 3.0 blades anymore, they've all moved on to 4.0/5.0. Going through all of the 3.0 ones listed as having good compatibility in the OP I was able to find a few for fairly reasonable prices on a couple different marketplaces.

I saw it mentioned in this thread that many PCIe 4.0 blades will have compatibility issues on a 5,1 Mac Pro unless used with a HighPoint or Sonnet PCIe 3.0 switched card. Are there any PCIe 4.0 blades confirmed to work fine on a 5,1 Mac Pro via slots 3/4 (albeit restricted to 1,500 mb/s)?

 

[pine_block]

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 MP61.0120.B00 for MP6,1). The new MP7,1 support booting from an NVMe SSD when external booting is enabled with Startup Security Utility.

Note that PCIe SSDs installed in a Mac Pro 5,1 (MP6,1 have exactly the same PCIe 2.0 limits too) are limited to ~1,500 MB/s unless installed on a PCIe switch card in slot 1 or 2 such as a HighPoint SSD7101A-1 or Amfeltec Squid that converts the Mac Pro PCIe 2.0 x16 to the PCIe 3.0 x4 needed for full throughput.

Also note that 3rd party SSDs have varying compatibility with the Mac Pro and not all listed below may be fully compatible.

macOS NVMe Support:​

• Genuine Apple NVMe drives are supported beginning with macOS Yosemite 10.10.2 with the correct firmware installed. 3rd party NVMe drives with 4096 bytes/sector are supported beginning with macOS Sierra with expanded support beginning with macOS High Sierra.
• macOS High Sierra, Mojave and Catalina supports both 4KiB and 512 bytes / sector NVMe drives.
• macOS Sierra supports 4KiB / sector drives like Apple OEM and some uncommon Toshiba/OCZ/Intel/WD blades. This post on InsanelyMac lists the blades that work with Sierra and hackintoshes, please note that most of those blades don't work with a Mac Pro at all or work with 750MB/s throughput only. Don't use this list to buy blades for a Mac Pro, it's linked here for information purposes only.
• For Sierra compatibility choose an NVMe blade that supports the 4Kn disk sector format. See 4Kn section below.
• Apple supports the 1.3 NVMe standard. Any blade that need a special NVMe module/driver won't be supported; seems that's the case with Samsung 970 EVO Plus without the firmware 2B2QEXM7 and some of the Plextor blades.
• To boot from a NVMe drive, for Mac Pro 5,1 you need to upgrade BootROM to at least 140.0.0.0.0, supplied with MAS Mojave full installers since 10.14.1. 10.14.4 has 141.0.0.0.0 and 10.14.5/10.14.6 have 144.0.0.0.0. For Mac Pro 6,1 you need to upgrade BootRom to at least MP61.0120.B00 included with macOS High Sierra 10.13.0.
• High Sierra boots/works perfectly both 4KiB and 512 bytes drives if you have MP5,1 BootROM 140/141/144.0.0.0.0.
• If you install MP5,1 BootROM 140/141/144.0.0.0.0, Sierra can boot from a 4KiB / sector NVMe M.2 blade.
• You can read about it on the first posts of these two threads:
  1. MP5,1: What you have to do to upgrade to Mojave
  2. MacPro5,1: BootROM thread

NVMe boot support and Mac Pro year models:
​

Mac Pro year model:	Model Identifier:	NVMe boot support:
2006 Mac Pro / Original Mac Pro	MacPro1,1	not possible, can't run Sierra/High Sierra. Native support for PCIe AHCI blades.
2007 Mac Pro / Mac Pro (8-Core)	MacPro2,1	not possible, can't run Sierra/High Sierra. Native support for PCIe AHCI blades.
Early 2008 Mac Pro	MacPro3,1	possible by loading NvmExpress driver via third party loaders such as OpenCore, RefindPlus/rEFInd etc (or after risky injection of NVMe EFI modules into the BootROM) and run 10.12/Newer*. Native support for PCIe AHCI blades.
Early 2009 Mac Pro	MacPro4,1	possible after replacing firmware with cross-flashed MacPro5,1 firmware (use or update to 144.0.0.0.0) or by loading NvmExpress driver via third party loaders such as OpenCore, RefindPlus/rEFInd etc and run 10.12/Newer*. Native support for PCIe AHCI blades.
Mid 2010 Mac Pro	MacPro5,1	upgrade to BootROM 140.0.0.0.0 or newer, current one is 144.0.0.0.0, and install 10.12/Newer* to have full native NVMe support.
Mid 2012 Mac Pro	MacPro5,1	upgrade to BootROM 140.0.0.0.0 or newer, current one is 144.0.0.0.0, and install 10.12/Newer* to have full native NVMe support.
Late 2013 Mac Pro	MacPro6,1	upgrade to BootROM MP61.0120.B00 or newer, current one from Monterey is 481.0.0.0.0, and install 10.12/Newer* to have full native NVMe support. Needs a 12+16 adapter to use standard M.2 blades.
2019 Mac Pro	MacPro7,1	native support, can boot from AHCI or NVMe blades/drives when external booting is enabled with Startup Security Utility.

* 10.12 only supports 4Kib / sector M.2 blades and U.2 drives while 10.13 and newer macOS releases supports both 4Kib /sector and 512 bytes / sector M.2 blades and U.2 drives.

What are internal storage for the Mac Pro firmware:
​

Mac Pro year model:	Model Identifier:	What Mac Pro firmware recognize as internal drives:
Mac Pro (2006)	MacPro1,1	SATA drives connected to the 6 southbridge SATA ports plus the two PATA drives connected to the PATA cable inside the ODD bay.
8-Core Mac Pro (2007)	MacPro2,1	SATA drives connected to the 6 southbridge SATA ports plus the two PATA drives connected to the PATA cable inside the ODD bay.
early-2008 Mac Pro	MacPro3,1	SATA drives connected to the 6 southbridge SATA ports plus the two PATA drives connected to the PATA cable inside the ODD bay.
early-2009 Mac Pro	MacPro4,1	SATA/SAS drives connected to the 4 southbridge SATA ports plus the two SATA drives connected to the SATA cable inside the ODD bay.
mid-2010 Mac Pro	MacPro5,1	SATA/SAS drives connected to the 4 southbridge SATA ports plus the two SATA drives connected to the SATA cable inside the ODD bay.
mid-2012 Mac Pro	MacPro5,1	SATA/SAS drives connected to the 4 southbridge SATA ports plus the two SATA drives connected to the SATA cable inside the ODD bay.
late-2013 Mac Pro	MacPro6,1	Only the 12+16 AppleOEM PCIe SSD is an internal drive.
2019 Mac Pro	MacPro7,1	Only the T2 Storage is an internal drive for T2 Security. While the two SATA ports of the logic board are internal for macOS, T2 Security definitions override macOS and you can only boot from SATA native ports with relaxed T2 Security, with external boot enabled with Startup Security Utility. Any PCIe connected storage are external for the firmware and T2 Security.

NVMe and AHCI Blades:
​

Apple SSDs: Proprietary Apple 12+16 pin to PCIe adapter needed for Mac Pro 5,1 & older and also 7,1. No adapter needed for Mac Pro 6,1. All Apple SSDs use 4KB sector size and have good compatibility.

Name	Interface	Tech	Sizes	Link	Speeds	Sector	Compatibility	Notes
SSUAX & SRIUP	AHCI	2D MLC	128GB, 256GB, 512GB, and 1TB	PCIe 2.0 x2 (128GB, 256GB, 512GB) PCIe 2.0 x4 (1TB)	~1,000 MB/s read ~800 MB/s write	4 KB	Good	Based on Samsung XP941 with UAX controller (S4LN053X01) and Toshiba with Marvell 88SS9183 controller
SSUBX	AHCI	2D MLC	128GB, 256GB, 512GB, and 1TB	PCIe 3.0 x4	~1,500 MB/s read ~1,425 MB/s write	4 KB	Good	Based on Samsung SM951 with UBX controller (S4LN058A01)
SSPOLARIS	NVMe	2D & 3D MLC or TLC	24GB, 32GB, 128GB, 256GB, 512GB, 1TB, and 2TB	PCIe 3.0 x4	~2,700 MB/s read ~2,350 MB/s write	4 KB	Good	Based on Samsung SM961 or PM961 with Polaris controller (S4LP077X01)
SSPHOTON	NVMe	48-layer MLC	32GB and ? (LPDDR4 DRAM)	PCIe 3.0 x2 ?	1,500 MB/s read, 900 MB/s write ?	4 KB	Good	Based on Samsung PM971 with Photon controller

Good article on Apple blade SSDs: The Ultimate Guide to Apple’s Proprietary SSDs

M.2 SSDs: M.2 PCIe adapter needed for Mac Pro 5,1 & 7,1. M.2 to proprietary Apple adapter needed for Mac Pro 6,1 or external Thunderbolt adapter.

Brand	Name	Interface	Tech	Sizes	Link	Speeds	Sector	4Kn	Compatibility	Notes
Samsung	XP941	AHCI	2D MLC	128GB, 256GB, and 512GB	PCIe 2.0 x2	~1,000 MB/s read ~800 MB/s write	512 B	Unknown	Good	UAX controller (S4LN053X01)
Samsung	SM951	AHCI & NVMe	2D MLC	128GB, 256GB, and 512GB	PCIe 3.0 x4	~2,150 MB/s read ~1,500 MB/s write	512 B	Unknown	Good	UBX controller (S4LN058A01) Datasheet (AHCI), Datasheet (NVMe)
Samsung	950 PRO	NVMe	3D MLC	256GB and 512GB	PCIe 3.0 x4	~2,500 MB/s read ~1,500 MB/s write	512 B	Unknown	Issues/not compatible	UBX controller (S4LN058A01) Datasheet
Samsung	PM961	NVMe	3D TLC	128GB, 256GB, 512GB, and 1TB	PCIe 3.0 x4	~3,000 MB/s read ~1,500 MB/s write	512 B	Unknown	Good	Polaris controller (S4LP077X01) Datasheet
Samsung	SM961	NVMe	2D & 3D MLC	128GB, 256GB, 512GB, and 1TB	PCIe 3.0 x4	~3,200 MB/s read ~1,800 MB/s write	512 B	Unknown	Good	Polaris controller (S4LP077X01) Datasheet
Samsung	960 EVO	NVMe	3D TLC	250GB, 500GB, and 1TB	PCIe 3.0 x4	~3,200 MB/s read ~1,900 MB/s write	512 B	Unknown	Good	Polaris controller (S4LP077X01) Datasheet
Samsung	960 PRO	NVMe	2D & 3D MLC	512GB, 1TB, and 2TB	PCIe 3.0 x4	~3,500 MB/s read ~2,100 MB/s write	512 B	Unknown	Good	Polaris controller (S4LP077X01) Datasheet
Samsung	PM981	NVMe	64-layer 3D TLC	256GB, 512GB, 1TB, and 2TB	PCIe 3.0 x4	~3,500 MB/s read ~2,400 MB/s write	512 B	Unknown	Issues/not compatible	Phoenix controller (S4LR020) Datasheet
Samsung	PM981a	NVMe	64-layer 3D TLC	256GB, 512GB, 1TB, and 2TB	PCIe 3.0 x4	~3,500 MB/s read ~2,400 MB/s write	512 B	Unknown	Issues/not compatible	Phoenix controller (S4LR020) Datasheet
Samsung	970 EVO	NVMe	96-layer 3D TLC	500GB and 1TB	PCIe 3.0 x4	~3,500 MB/s read ~2,500 MB/s write	512 B (emulated), 4 KB physical	Unknown	Good	Phoenix controller (S4LR020) Datasheet
Samsung	970 EVO+	NVMe	96-layer 3D TLC	250GB, 500GB, 1TB and 2TB	PCIe 3.0 x4	~3,500 MB/s read ~3,300 MB/s write	512 B (emulated), 4 KB physical	No	Requires at least firmware 2B2QEXM7 to work with macOS, all blades manufactured since September/October 2019 have the Mac Pro compatible firmware	Phoenix controller (S4LR020) Datasheet Not recommended for use in the Mac Pro 6,1 because it operates at a higher temperature than other NVMe blades. About 10-15 degrees C warmer than SK Hynix and Toshiba/KIOXIA NVMe blades.
Samsung	970 PRO	NVMe	64-layer 3D MLC	512GB and 1TB	PCIe 3.0 x4	~3,500 MB/s read ~3,000 MB/s write	512 B (emulated), 4 KB physical	Unknown	Good	Phoenix controller (S4LR020) Datasheet
Samsung	980	NVMe							Issues/not compatible	Firmware problems, incompatibility with PCIe v2.0, but works with PCIe v3.0 switched adapter
Samsung	980 PRO	NVMe							Issues/not compatible	Firmware problems, endurance problems, incompatibility with PCIe v2.0, but works with PCIe v3.0 switched adapter
Samsung	990 PRO	NVMe							Issues/not compatible	Firmware problems, endurance problems, incompatibility with PCIe v2.0, but works with PCIe v3.0 switched adapter
Intel	660p	NVMe	3D QLC	1TB	PCIe 3.0 x4			Unknown	Good	SM2263EN controller
Intel	670p	NVMe	3D QLC	512GB, 1TB and 2TB	PCIe 3.0 x4			Unknown	Issues/not compatible	Performance issues, freezes.
Intel	Optane 900p	NVMe	3D XPoint	280GB and 480GB	PCIe 3.0 x4	~1,500 MB/s		Unknown	Good	Half Height Half Length (HHHL) Add-in-Card Datasheet
HP	EX920	NVMe	3D TLC	256GB, 512GB, 1TB, and 2TB	PCIe 3.0 x4	~3,200 MB/s read ~1,800 MB/s write		Unknown	Good	SM2262 controller Datasheet
HP	EX950	NVMe	3D TLC	512GB, 1TB, and 2TB	PCIe 3.0 x4	~3,500 MB/s read ~2,900 MB/s write		Unknown	Unknown (may have issues: see post #1,733)	Datasheet
Toshiba/KIOXIA	XG5	NVMe	64 layer BiCS3 3D TLC	256GB, 512GB, and 1TB	PCIe 3.0 x4	~3,000 MB/s read ~2,100 MB/s write	512 B (emulated), 4 KB physical	Yes	Good	TC58NCP090GSD controller Datasheet
Toshiba/KIOXIA	XG5-P	NVMe	64 layer BiCS3 3D TLC	1TB and 2TB	PCIe 3.0 x4	~3,000 MB/s read ~2,200 MB/s write	512 B (emulated), 4 KB physical	Yes	Good	TC58NCP090GSD controller Datasheet
Toshiba/KIOXIA	XG6	NVMe	96 layer BiCS4 3D TLC	256GB, 512GB, and 1TB	PCIe 3.0 x4	~3,180 MB/s read ~2,960 MB/s write	512 B (emulated), 4 KB physical	Yes	Good	TC58NCP090GSD controller Datasheet @zhpenn is using one with a MP7,1
Toshiba/KIOXIA	XG6-P	NVMe	96 layer BiCS4 3D TLC	2TB	PCIe 3.0 x4	~3,180 MB/s read ~2,920 MB/s write	512 B (emulated), 4 KB physical	Yes	Good	TC58NCP090GSD controller Datasheet
SanDisk	Ultra 3D	NVMe	96 layer 3D TLC	250GB, 500GB, 1TB	PCIe 3.0 x4	~2400 MB/s read ~1950 MB/s write		Unknown	Issues/not compatible (don't work from cold boot/sleep issues/KPs)	rebadge of WD SN550 with same controller and firmware Sandisk / Controller DRAM less Datasheet
Western Digital	WD Black	NVMe	3D TLC	250GB, 500GB, 1TB	PCIe 3.0 x4	~ MB/s read ~ MB/s write		Unknown	Unknown	Datasheet
Western Digial	WD Blue SN550	NVMe	96 layer 3D TLC	250GB, 500GB, 1TB	PCIe 3.0 x4	~2400 MB/s read ~1950 MB/s write		Unknown	Issues/not compatible (don't work from cold boot/sleep issues/KPs)	Controller DRAM less Datasheet
Western Digial	WD Blue SN570	NVMe	96 layer 3D TLC	250GB, 500GB, 1TB, 2TB	PCIe 3.0 x4	~3500 MB/s read ~1950 MB/s write		Unknown	Issues/not compatible (don't work from cold boot/sleep issues/KPs), not detected with MacPro6,1	Controller DRAM less Datasheet
Western Digital	WD Black SN750	NVMe	64-layer 3D TLC	250GB, 500GB, 1TB, 2TB	PCIe 3.0 x4	~3400 MB/s read ~2900 MB/s write		Unknown	Good	Datasheet
Western Digital	WD Black SN770	NVMe 1.4	112-layer 3D TLC	250GB, 500GB, 1TB, 2TB	PCIe 4.0 x4	~5150 MB/s read ~4850 MB/s write		Unknown	Issues/not compatible (multiple reports of KPs when in high load, only works at 2,5GT/s with slots 3 and 4) Working OK in MP 6.1 report Do not buy it for a MacPro5,1 without a PCIe switched adapter.	DRAM-less
Sabrent	Rocket	NVMe	Toshiba 3D TLC	256GB, 512GB, 1TB, 2TB, and 4TB	PCIe 3.0 x4	~3,450 MB/s read ~3,000 MB/s write	512 B (emulated), 4 KB physical	Yes	Good	Phison E12 or E16 controller Datasheet
Sabrent	Rocket Q	NVMe	Micron 96L 3D QLC	500GB, 1TB, 2TB, 4TB, and 8TB	PCIe 3.0 x4	~3,400 MB/s read ~3,000 MB/s write	512 B (emulated), 4 KB physical	Yes	Good	Phison E12S controller Datasheet
SK Hynix	PC401	NVMe		256GB, 512GB, and 1TB		~2,700 MB/s read ~1,450 MB/s write	512 B (emulated), 4 KB physical	Yes	Unknown
SK Hynix	PC601	NVMe		256GB, 512GB, and 1TB		~3,400 MB/s read ~2,500 MB/s write	Unknown (most likely 512 B (emulated), 4 KB physical)	Unknown (most likely yes)	Unknown
SK Hynix	Gold P31	NVMe	128 layer 4D NAND	500GB, 1TB, and 2TB		~3,200 MB/s read ~3,200 MB/s write	512 B (emulated), 4 KB physical	Yes	Good (requires latest firmware)	SK Hynix controller
ADATA	XPG SX8200 Pro	NVMe		256GB, 512GB, 1TB, and 2TB		~3,500 MB/s read ~3,000 MB/s write	4 KB	-	Good	Datasheet
Crucial	P5	NVMe		250GB, 500GB, 1TB, and 2TB		~3,400 MB/s read ~3,000 MB/s write	Unknown	Unknown	Caution (This user reports it working well in a MacBook Pro, while this user reports it is not.)	Datasheet
Crucial	P3	NVME		2TB			Unknown	Unknown	Good	Works in MP5.1
Mushkin	Helix-L	NVMe		120GB, 250GB, 500GB, 960GB, 1TB		~2,100 MB/s read ~1,700 MB/s write	Unknown	Unknown	Good	SMI SM2263XT controller
Corsair	MP400	NVMe	Micron 96 layer QLC	1TB, 2TB, 4TB, 8TB	PCIe 3.0	~3480 Mbps read ~3000 Mbps write	Unknown	Unknown	Good	Phison E125 controller depending on blade size, from random 190 000 read to random 710 000 write
Kingston	FURY Renegade	NVMe	3D TLC (Micron TLC 167)	500GB, 1TB, 2TB, 4TB	PCIe 4.0	~1,407 MB/s read* ~1,327 MB/s write*			Good (MP6,1)	(*)speeds limited by MP6,1; Phison E18 controller (PS5018-E18); operates at ~40°C with additional cooler in MP6,1

Recommended PCIe adaptors for Mac Pro 5,1 & 7,1:

Standard PCIe x4 cards (tops at 1500 MB/s with MP5,1, double with MP7,1)(no switch):​

Low cost:

Be warned, don't use AHCI and NVMe blades without having a heatsink installed, you will have thermal throttling frequently and may cook your blade.

• RIITOP M.2 NVMe to PCIe Adapter [M2TPCE16X] with HEAT SINK - operates at PCIe x4 but keyed to fit 4x/8x/16x slot - good for low cost NVMe M.2 upgrade where PCIe x4 speed is sufficient, low profile does not impede GPU air cooling if used in slot 2
• Lycom DT-120
• Micro Connectors M.2 NVMe + M.2 SATA 80mm SSD PCIe x4 Adapter with Heat Sink - Model PCIE-M20802HS (only the M.2 NVMe slot has been tested)
• For proprietary 12+16 Apple SSDs (usually Apple blades used on Macs from 2013~2015): generic adapter from eBay (e.g. "2013-2014 Macbook Air SSD PCIe adapter 4X") (no brand)

Medium cost:

All adapters have heatsinks.

• Angelbirds Wings PX1 (officially discontinued in February 2019, prices from 3rd party resellers are starting to soar).
• Aqua Computer kryoM.2 - original model, without the heatsink for the underside of the blade that EVO model has. This model supports both single and doubled sided blades.
• Aqua Computer kryoM.2 evo thread Aqua Computer kryoM.2 evo PCIe 3.0 x 4, adapter. This model supports only single sided blades. If you don't install the second heatsink, at the back of the PCB, you can use double sided blades.
• Wolftech pulsecard - made by Angelbird for Wolftech, it's exactly the same as Wings PX1, but without the LED illumination.

PCIe x8 & x16 switch cards (up to ~6200MB/s with MP5,1, double with MP7,1):​

Better performance / higher cost (up to 3,000 MB/s with MP5,1, double with MP7,1), tested in the thread:

• IO Crest IO-PCE2824-TM2 (aka Syba SI-PEX40129): Supports 2 blade SSDs. Uses ASMedia x8 ASM2824 switch. Heatsink with a fan over the blades and PCIe switch. Up to 2900MB/s with MP5,1 and a little less than 6000MB/s total throughput with MP7,1. Warning: several recent posts ( #2,146 , #2,204 ) that recently I/O Crest cards are freezing with MP5,1. Seems newer cards are now incompatible.
• OWC ACCELSIOR 4M2 Supports four (seems to require single side M.2 blades, to be confirmed) 80mm M.2 blades. Uses x8 ASMedia ASM2824 switch. Heatsink over the blades and PCIe switch. It's a PCIe 3.0 x8 card, ~2900MB/s with MP5,1 PCIe 2.0 slot1 and slot2 and double that with MP7,1 PCIe 3.0 slots. Several reports that the original version have problems with 2019 Mac Pro and only the revised version works with MP7,1.
• Ableconn PEXM2-130: dual-blade ASM2824 switch. Runs without a fan, needs discrete heatsinks for each blade. Boots MacOS and Windows, up to 3000 MB/s with MP5,1.

Top performance / high cost [tops at 3200 MB/s with one blade, 6200 MB/s (10000~120000 MB/s for MP7,1) with two to four], all tested in the thread:

• Amfeltec Squid: Amfeltec x16 PCIe with 4 SSDs: 5900+ MB/s. Supports four double side M.2 blades, up to 110mm. The PCI Express Gen 3 version uses PLX PEX8732 switch. Just a heatsink and fan for the PCIe switch, no heatsink for the blades. The Gen 2 version doesn't have a fan and doesn't allow full speed from individual Gen 3 SSDs.
• Amfeltec Squid PCI Express Gen 3 Carrier Board for 6 M.2 or NGFSS (NF1) SKU-086-36 Supports six double side M.2 blades, up to 110mm, 32mm wide. Uses x16 PLX PEX87xx switch? Just a heatsink for the PCIe switch, two fans for the blades. Link for the manual: Squid PCIe Gen 3 Carrier BoardTM for six M.2 / NGSFF(NF1) SSD modules (SKU-086-36). Works with MP5,1 and MP7,1.
• HighPoint SSD7101A-1: Highpoint 7101A - PCIe 3.0 SSD performance for the cMP. Supports four double side M.2 blades, up to 110mm. Uses PLX PEX8747 switch. Heatsink with a fan over the blades and PCIe switch. This card can boot Windows when using NVMe blades and UEFI install.
• Sonnet M.2 4x4 PCIe Card FUS-SSD-4X4-E3: Supports four single sided 80mm M.2 blades. Uses x16 PLX PEX8747 switch. Heatsink with a fan over the blades and PCIe switch. Needs a GPU with pre-boot configuration support. Almost too big to fit MP5,1 length wise. Do not buy it if you need to boot Windows from the blades or will upgrade to a PC later; this card can't boot Windows. Sonnet has a support document about what major blades are single and double sided:
  https://sonnettech.com/support/downloads/manuals/M2_compatibility.pdf

Product	Unique	PCIe	Lanes	Chipset	Boot	M.2 Sockets	Speed MB/s
Amfeltec Squid SKU-086-34	Has offset PCI Slot 2 cMP5,1	Gen 3 x4/x8 PCIe 2.1	32	PLX PEX8732	✅	4x NVME M2 1.0 2210 2280 2260 2242 2230	5900+
Amfeltec Squid SKU-086-36	Has offset PCI Slot 2 cMP5,1 aux Power	Gen 3 x16 x4/x8Optional Gen 3 x8 PCIe 2.1		unknown	unknown	6x 110mm NVME M2 1.1 2210 2280
HighPoint SSD7101A-1			48	PLX PEX8747	✅ W ✅	4x NVME M2
Sonnet FUS-SSD-4X4-E3	Long			PLX PEX8747	✅ W ⛔

Untested in the thread yet, but should work:

• Amfeltec Squid PCI Express Gen 3 Carrier Board for 2 M.2 or NGFSS (NF1) SKU-086-32: Supports two double side M.2 blades, up to 110mm, 32mm wide. Uses a x8 PLX PEX87xx switch? Just a heatsink for the PCIe switch, one fan for the blades. Very cost effective. Link for the manual Squid PCI Express Gen3 Carrier BoardTM for 2 M.2 SSD modules. Untested in the Mac Pro.
• HighPoint SSD7140: Supports eight PCIe Gen 3 M.2 blades.
• HighPoint SSD7180: Supports eight PCIe Gen 3 U.2 devices.
• HighPoint SSD7184: Supports eight PCIe Gen 3 x4 devices (four U.2 and four external PCIe).
• HighPoint SSD7505: Supports four PCIe Gen 4 M.2 blades.
• HighPoint SSD7540: Supports eight PCIe Gen 4 M.2 blades.
• HighPoint SSD7580: Supports eight PCIe Gen 4 U.2 devices.
• Liqid Element LQD4500: Supports eight PCIe Gen 4 M.2 blades. Requires 6-pin PCIe power. Although Macs don't have PCIe Gen 4 yet, the card has a PCIe Gen 4 switch that should allow max performance from two or three Gen 4 NVMe devices. I don't think you can get a LQD4500 without M.2 devices already installed?

Recommended M.2 to Apple 12+16 pin adapters for Mac Pro 6,1:
​

• Sintech ST-NGFF2013-C: Supports one M.2 blade​
• Amfeltec AngelShark Carrier Board™ for M.2 SSD modules: Supports two M.2 blades plus one Apple 12+16 pin blade, or three M.2 blades using a single 12+16 pin adapter on the board. Note: All SSDs installed on the carrier board are seen as external by the Mac Pro, even the original Apple SSD. It must be removed to update the system firmware (boot ROM). ​

Don't buy PCIe adapters list:​

Any multiple M.2 blades card from ASRock/Asus/Gigabyte/MSI that don't have a PCIe 3.0 switch and requires a motherboard with PCI Express Lane Partitioning support, also known as bifurcation support, like the cards listed on the table below.

It's confirmed that off MP7,1 PCIe slots, just the two MPX ones are connected to the CPU and the rest are behind a 96-lane PEX8796 PCIe switch, so no PCI Express Lane Partitioning support for 2019 Mac Pro, and the same requirements for PCIe M.2/U.2 adapters as MP5,1 are valid, the only difference is that 2019 Mac Pro slots are PCIe 3.0.

Being crystal clear, 2019 Mac Pro doesn't support the cheap multiple M.2 adapters that require motherboard bifurcation support and only the first blade of the four is recognized. While MP7,1 has a chipset compatible with lane bifurcation, no Mac has the firmware or the configuration options necessary for it to work.

No blade works when the cards that require PCI Express Lane Partitioning support of the table below are installed on a MP5,1, the chipset is too old and don't support it at all.

Adapter:	Impediment for not working:	Issues:
ADWITS Quad M.2	bad design, requires MOLEX or SATA power even with 1 blade. @combatphotog bought one and tested, card keeps shutting down his MP5,1.	Power via Molex
Aplicata Quad M.2 NVMe SSD PCIe x16 Adapter	requires motherboard PCI Express Lane Partitioning support (aka bifurcation)	PCIe Bifurcation
ASRock Ultra Quad	requires motherboard PCI Express Lane Partitioning support (aka bifurcation)	PCIe Bifurcation
Asus Hyper M.2 x16 Asus Hyper M.2 x16 v2 Asus Hyper M.2 x16 Gen 4	requires motherboard PCI Express Lane Partitioning support (aka bifurcation). Confirmed working for one blade, not working for more than one.	PCIe Bifurcation ASUS Support Note
CEACENT ANM22PE08 NVMe Controller PCIe 3.0 x8 to M.2 Dualport with heatsink	requires motherboard PCI Express Lane Partitioning support (aka bifurcation)	PCIe Bifurcation
Dell Ultra-Speed Drive Quad NVMe M.2 PCIe x16 Card	requires motherboard PCI Express Lane Partitioning support (aka bifurcation)	PCIe Bifurcation
GIGABYTE AORUS PCIE x16 M.2 GIGABYTE AORUS Gen4 AIC Adaptor GC-4XM2G4	requires motherboard PCI Express Lane Partitioning support (aka bifurcation)	PCIe Bifurcation
GIGABYTE CMT2014, CMT4032 and CMT4034	requires motherboard PCI Express Lane Partitioning support (aka bifurcation)	PCIe Bifurcation
HP Z Turbo Drive Quad Pro	requires motherboard PCI Express Lane Partitioning support (aka bifurcation)	PCIe Bifurcation
MSI Xpander-Aero	requires motherboard PCI Express Lane Partitioning support (aka bifurcation)	PCIe Bifurcation
Squid PCIe Gen 3 Carrier Board for 4 M.2 SSD modules (M-key ) (full or half-height bracket) SKU-086-B4	requires motherboard PCI Express Lane Partitioning support (aka bifurcation)	PCIe Bifurcation
Supermicro AOC-SLG3-2M2	requires motherboard PCI Express Lane Partitioning support (aka bifurcation)	PCIe Bifurcation
Supermicro AOC-SLG3-8E2P	fried @handheldgames Mac Pro	⛔
Synology M2D18	it's a ~$200 PCIe 2.0 switch card with SATA + M2 that tops at 1500MB/s

Is it a hard and fast rule that SSDs with DRAM-less controllers are a no go for the 5,1? It seems to be the common sticking point in this list but I can not find an explanation for it anywhere.