Sidebar Sidebar
Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.

Recommendations on slot and PCIe adapter

M

matthewpomar

macrumors member
Original poster
Oct 27, 2010
79
12
I will be flashing my 2009 Mac Pro to version 140.0.0.0.0 Boot ROM using macOS Mojave installer. My Mac is currently only being used for VM in Windows only, and based on other feedback from this forum, bring the Boot Rom up to latest version may increase PCIe speeds for Windows as well as Mac.

Windows 8.1 will be running on an NVMe blade. I do not yet have an adapter nor know which slot to install this NVMe drive into as I have been reading there are performance differences for using 2, vs 3/4.

I don't care about boot times as much as good performance once I boot.

Any recommendations on which slot I should install the NVMe drive?

Any recommendations on a single blade NVMe adapter, or are they all the same?

P.S. I also read that the High Point SSD7101A-1 may give me the best performance for a single NVMe blade if installed in slot 2, but it's not the cost for my needs at this time.
 
matthewpomar said:
Thank you! The IO Crest IO-PCE2824-TM2 looks like a great middle of the road option.

Do you know if it supports a single NVMe blade while achieving its full speed potential? That is, will a single NVMe blade get PCIe 3.0 speeds if installed in slot 2?
Click to expand...
A fast blade like Samsung 970 Pro will not get full PCIe 3.0 X4 speeds, but a little less than 3000MB/s, this is the limit of the ASMedia 8x PCIe switch used by IOCrest.
 
  • Like
Reactions: yukdave and matthewpomar
tsialex said:
A fast blade like Samsung 970 Pro will not get full PCIe 3.0 X4 speeds, but a little less than 3000MB/s, this is the limit of the ASMedia 8x PCIe switch used by IOCrest.
Click to expand...

Thank you for the clarification. Will a single Samsung 970 Pro perform faster with IO Crest card vs a lower-cost card like the Lycom DT-120?

Appreciate your help.
 
matthewpomar said:
Thank you for the clarification. Will a single Samsung 970 Pro perform faster with IO Crest card vs a lower-cost card like the Lycom DT-120?

Appreciate your help.
Click to expand...

Throughput of Samsung 970 PRO installed in a MP5,1 with:

  • Adapter without a PCIe switch: ~1450MB/s
  • Adapter with a 8x PCIe switch: ~2900MB/s
  • Adapter with a 16x PCIe switch: ~3200MB/s (full capacity of 970 PRO, future faster blades will have even more throughput, up to ~3940MB/s theoretical limit)
 
Last edited:
  • Like
Reactions: Le_Cactus, matthewpomar and crjackson2134
tsialex said:
Throughput of Samsung 970 PRO installed in a MP5,1 with:

  • Adapter without a PCIe switch: ~1450MB/s
  • Adapter with a 8x PCIe switch: ~2900MB/s
  • Adapter with a 16x PCIe switch: ~3200MB/s (full capacity of 970 PRO, future faster blades will have even more throughput, up to ~3940MB/s theoretical limit)
Click to expand...

Thanks for the summary.

If I go with the IO Crest 8x PCIe switch, can I have a Samsung 970 Pro in one slot for Windows and a Samsung 970 Pro in the other slot for Mac and be able to dual boot and still achieve the ~2900MB/s speed, or will filling the other slot (even if not used) somehow limit the speed?
 
matthewpomar said:
Thanks for the summary.

If I go with the IO Crest 8x PCIe switch, can I have a Samsung 970 Pro in one slot for Windows and a Samsung 970 Pro in the other slot for Mac and be able to dual boot and still achieve the ~2900MB/s speed, or will filling the other slot (even if not used) somehow limit the speed?
Click to expand...
Windows don't support installs with external disks, NVMe blades are external disks to the Mac Pro firmware.

You can hack it, but it's a constant headache with Windows Updates, totally not worth. People will tell you that it can be overcome, it will work, but the maintenance costs and constant clone to and back to a SATA drive for updates it's a hassle. Use a SATA SSD for Windows and forget Windows + NVMe + Mac Pro 5,1.

The blade being used at the moment gets the throughput. If you are doing simultaneous access, it's shared.
 
Last edited:
tsialex said:
Windows don't support installs with external disks, NVMe blades are external disks to the Mac Pro firmware.
Click to expand...

I have been booting Windows 8.1 for several years from an AHCI PCIe drive without hacks, even though it shows as external in macOS. I simply installed Windows using the regular installer, and it shows up as EFI Boot when holding down Option key.

Are you suggesting that booting into Windows running on an NVMe drive doesn't work without hacks, even though booting from an AHCI drive works without applying any hacks?

Thank you.
 
matthewpomar said:
I have been booting Windows 8.1 for several years from an AHCI PCIe drive without hacks, even though it shows as external in macOS. I simply installed Windows using the regular installer, and it shows up as EFI Boot when holding down Option key.

Are you suggesting that booting into Windows running on an NVMe drive doesn't work without hacks, even though booting from an AHCI drive works without applying any hacks?

Thank you.
Click to expand...
Windows won’t install to a NVMe drive in a Mac Pro.

You have to clone from a SATA disk or use VMWARE Fusion to indirectly do the install.

This is easy to prove, just try to install W10 to a NVMe drive, you will see that the installer won’t let you.
 
Last edited:
Noted about the installation woes.

But if I were to clone the Windows 8.1 image from the bootable AHCI blade to the NVMe blade, should I in theory be able to boot from it on the Mac Pro?

From what I have read, Windows 8.1 support NVMe boot. Would it work if I update the firmware to 140.0.0.0.0?

Thanks again.
 
matthewpomar said:
Noted about the installation woes.

But if I were to clone the Windows 8.1 image from the bootable AHCI blade to the NVMe blade, should I in theory be able to boot from it on the Mac Pro?

From what I have read, Windows 8.1 support NVMe boot. Would it work if I update the firmware to 140.0.0.0.0?

Thanks again.
Click to expand...
You should test it.

For NVMe boot you just need to upgrade to any Mac Pro firmware after 140.0.0.0.0.
 
  • Like
Reactions: bsbeamer
You must log in or register to reply here.
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.
Top Bottom
Back